LOJ 1058

#include <bits/stdc++.h>
// #include <iostream>
// #include <cstdio>
// #include <cstdlib>
// #include <algorithm>
// #include <cmath>
// #include <vector>
// #include <set>
// #include <map>
// #include <queue>
// #include <stack>
// #include <ctime>
// #include <cassert>
// #include <complex>
// #include <string>
// #include <cstring>
// #include <bitset>
using namespace std;

// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC optimize("unroll-loops")

#define ll              long long int
#define vi              vector< int >
#define vll             vector< ll >

#define sc              scanf
#define pf              printf
#define cspf(i)         pf("Case %d: ", i)
#define spc             pf(" ")
#define line            pf("\n")

#define ff              first
#define ss              second
#define mp              make_pair
#define pb              push_back
#define ppb             pop_back
#define tp(v,j)         get<j>(v)
#define Log(b,x)        (log(x)/log(b))

#define FOR(i,x,y)      for(int i = int(x); i < int(y); i++)
#define ROF(i,x,y)      for(int i = int(x)-1; i >= int(y); i--)
#define clr(arr,x)      memset(arr, x, sizeof arr)
#define vout(v,sz)      for(int w=0;w<sz;w++){if(w) spc; cout<<v[w];}
#define all(v)          v.begin(), v.end()
#define rall(v)         v.rbegin(), v.rend()
#define unq(v)          sort(all(v)),(v).resize(unique(all(v))-v.begin())
#define fastIO          ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr)

#define sc1(x)          sc("%d",&x);
#define sc2(x,y)        sc("%d %d", &x, &y)
#define sc3(x,y,z)      sc("%d %d %d", &x, &y, &z)
#define scl1(x)         sc("%lld",&x);
#define scl2(x,y)       sc("%lld %lld", &x, &y)
#define scf1(x)         sc("%lf",&x);
#define scf2(x,y)       sc("%lf %lf", &x, &y)

#define pf1(x)          pf("%d",x);
#define pf2(x,y)        pf("%d %d", x, y)
#define pfl1(x)         pf("%lld",x);
#define pfl2(x,y)       pf("%lld %lld", x, y)

#define MOD             (int)(998244353)
#define MaxN            100000
#define inf             0x3f3f3f3f
#define PI              acos(-1.0)  // 3.1415926535897932
#define eps             1e-9

#ifdef ERFANUL007
    #define debug(...) __f(#__VA_ARGS__, __VA_ARGS__)
    template < typename Arg1 >
    void __f(const char* name, Arg1&& arg1){
        cout << name << " = " << arg1 << std::endl;
    }
    template < typename Arg1, typename... Args>
    void __f(const char* names, Arg1&& arg1, Args&&... args){
        const char* comma = strchr(names, ',');
        cout.write(names, comma - names) << " = " << arg1 <<" | ";
        __f(comma+1, args...);
    }
#else
    #define debug(...)
#endif

template <class T> inline T bigMod(T p,T e,T M){T ret=1; for(;e>0;e>>=1){ if(e&1) ret=(ret*p)%M; p=(p*p)%M;} return (T)ret;}
template <class T> inline T modInverse(T a,T M){return bigMod(a,M-2,M);}
template <class T> inline T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template <class T> inline T lcm(T a,T b) {a=abs(a);b=abs(b); return (a/gcd(a,b))*b;}

int dx[] = { 1,-1, 0, 0};                //graph moves
int dy[] = { 0, 0, 1,-1};               //graph moves

struct PT{
    int x, y;
    void scan(){ scanf("%d %d",&x,&y);}
};


double SQ(double x){ return x*x;}

double Dis(PT a,PT b){ return SQ(a.x - b.x) + SQ(a.y - b.y);}

double absDis(PT a,PT b){ return sqrt(Dis(a,b));}

/*two vector lines Dot product*/
int Dot(PT a,PT b){ return a.x*b.x + a.y*b.y;}

/*two vector lines Cross product*/
int Cross(PT a,PT b){ return a.x*b.y - b.x*a.y;}

/*convert degree to radian*/
double toRadian(double x){ return (x*(PI/180.0));}

/*convert radian to degree*/
double toDegree(double x){ return (x*(180.0/PI));}

/*two point's vector line*/
PT vect(PT a,PT b){ return {a.x-b.x, a.y-b.y};}

/*convert a coordinate p from cartesian to polar
r = sqrt(x*x + y*y)
theta = atan(y/x) [in radian]*/
// PT toPolar(PT p){
//     return {sqrt(SQ(p.x)+SQ(p.y)), atan(p.y/p.x)};
// }

/*convert a coordinate p from polar to cartesian
theta must be radian
x = r * cos(theta)
y = r * sin(theta)*/
// PT toCartesian(PT a){
//     return {a.x * cos(a.y), a.x * sin(a.y)};
// }

/*divide line ab into m:n and return midpoint*/
/*For 3D add the z part same as x and y*/
// PT divideLine(PT a, PT b, double m, double n){
//     return {(a.x * m + b.x * n)/(m+n),
//         (a.y * m + b.y * n)/(m+n)};
// }

/*line ab to point c
0 => if ab and c coliner
+ => clockwise
- => anticlockwise
*/
int orientation(PT a, PT b, PT c)
{
    return (b.y-a.y)*(c.x-b.x)-(b.x-a.x)*(c.y-b.y);
}

struct Rectangle
{
    int fig;
    PT A, B, C, D;
    void scan(int _fig){
        A.scan();
        C.scan();
        B = {C.x, A.y};
        D = {A.x, C.y};
        fig = _fig;
    }
    bool inside(PT P){
        int val1 = orientation(A, B, P);
        int val2 = orientation(B, C, P);
        int val3 = orientation(C, D, P);
        int val4 = orientation(D, A, P);
        if(val1 == val2 && val2 == val3 && val3 == val4) return true;
        return false;
    }
};

struct Circle
{
    int fig;
    PT A;
    double r;
    void scan(int _fig){
        A.scan();
        scanf("%lf", &r);
        fig = _fig;
    }
    bool inside(PT P){
        double dis = absDis(A, P);
        if(dis + eps < r) return true;
        return false;
    }
};

struct Triangle
{
    int fig;
    PT A, B, C;
    void scan(int _fig){
        A.scan();
        B.scan();
        C.scan();
        fig = _fig;
    }
    bool inside(PT P){
        int val1 = orientation(A, B, P);
        int val2 = orientation(B, C, P);
        int val3 = orientation(C, A, P);
        if(val1 == val2 && val2 == val3) return true;
        return false;
    }
};

/*line ab and line cd is parrallel if ab X cd = 0 */
bool ifParallel(PT a,PT b,PT c,PT d)
{
    if(Cross(vect(a,b),vect(c,d)) != 0) // for double abs(val) > eps
        return false;
    return true;
}

/*line ab and line cd is perpendicular if ab . cd = 0 */
bool ifPerpendicular(PT a,PT b,PT c,PT d)
{
    if(Dot(vect(a,b),vect(c,d)) != 0) // for double abs(val) > eps
        return false;
    return true;
}

/*Area*/

double heronTriangle(double a, double b, double c){
    double s = (a + b + c) / 2.0;
    if(s - a < 0) return -1;
    if(s - b < 0) return -1;
    if(s - c < 0) return -1;
    return sqrt(s * (s - a) * (s - b) * (s - c));
}

double mdedianTriangle(double a, double b, double c){
    double s = (a + b + c) / 2.0;
    if(s - a < 0) return -1;
    if(s - b < 0) return -1;
    if(s - c < 0) return -1;
    return (4.0 / 3.0 ) * sqrt(s * (s - a) * (s - b) * (s - c));
}

double trapeziumArea(double a, double b, double h){
    return (a + b) * h / 2.0;
}

///Area of irregular polygon
double AreaOfPolygon(int n,PT a[])
{
    double area = 0.0;
    for(int i=1;i<n;i++){
        area+=(a[i-1].x*a[i].y-a[i].x*a[i-1].y);
    }
    area+=(a[n-1].x*a[0].y-a[0].x*a[n-1].y);
    return area/2.0;
}

/*volumn*/

double coneVolume(double r, double h){
    return PI * r * r * h / 3.0;
}

double CircumcircleR(double a, double b, double c){
    if(a + b + c < eps) return 0;
    return (a * b * c) / sqrt((a + b + c) * (b + c - a) * (c + a - b) * (a + b - c));
}

double IncircleR(double a, double b, double c){
    if(a + b + c < eps) return 0;
    return 2.0 * heronTriangle(a, b, c) / (a + b + c);
}

bool insideRectangle(PT p, PT a, PT c){
    if(p.x < a.x or p.x > c.x) return false;
    if(p.y < a.y or p.y > c.y) return false;
    return true;
}

/*checking shapes*/

bool isSquare(PT *a){
    if(abs(Dis(a[0], a[1]) - Dis(a[1], a[2])) > eps
        or abs(Dis(a[1], a[2]) - Dis(a[2], a[3])) > eps
        or abs(Dis(a[2], a[3]) - Dis(a[3], a[0])) > eps)
        return false;
    if(!ifPerpendicular(a[0], a[1], a[1], a[2])) return false;
    return true;
}

bool isRectangle(PT *a){
    if(abs(Dis(a[0], a[1]) - Dis(a[3], a[2])) > eps
        or abs(Dis(a[1], a[2]) - Dis(a[0], a[3])) > eps)
        return false;
    if(!ifPerpendicular(a[0], a[1], a[1], a[2])) return false;
    return true;
}

bool isRombus(PT *a){
    if(abs(Dis(a[0], a[1]) - Dis(a[1], a[2])) > eps
        or abs(Dis(a[1], a[2]) - Dis(a[2], a[3])) > eps
        or abs(Dis(a[2], a[3]) - Dis(a[3], a[0])) > eps)
        return false;
    return true;
}

bool isParallelogram(PT *a){
    if(abs(Dis(a[0], a[1]) - Dis(a[3], a[2])) > eps
        or abs(Dis(a[1], a[2]) - Dis(a[0], a[3])) > eps)
        return false;
    return true;
}

bool isTrapezium(PT *a){
    if(!ifParallel(a[0], a[1], a[3], a[2])
        and !ifParallel(a[1], a[2], a[0], a[3])) return false;
    return true;
}


PT f; //init first coordinate
//for clockwise sorting
bool ClockCmp(PT &a,PT &b){ return (f.x-a.x)*(f.y-b.y)<(f.x-b.x)*(f.y-a.y);}

//for anti-clockwise sorting
bool AClockCmp(PT &a,PT &b){ return (f.x-a.x)*(f.y-b.y)>(f.x-b.x)*(f.y-a.y);}

vector< ll > vv;

int main()
{
    #ifndef ONLINE_JUDGE
        clock_t tStart = clock();
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif

    int t, ca=0; sc1(t);

    while(t--){
        vv.clear();
        int n; sc1(n);
        PT a[n];
        FOR(i, 0, n) a[i].scan();
        for(int i=0; i<n; i++){
            for(int j=i+1; j<n; j++){
                int val1 = a[i].x + a[j].x;
                int val2 = a[i].y + a[j].y;
                ll val = ((ll)val1 << 32) ^ val2;
                vv.pb(val);
            }
        }
        sort(all(vv));
        ll ans = 0, cnt=1;
        for(int i=1; i<vv.size(); i++){
            if(vv[i] == vv[i-1]) cnt++;
            else{
                ans += (cnt*(cnt-1))/2;
                cnt = 1;
            }
        }
        ans += (cnt*(cnt-1))/2;
        printf("Case %d: %lld\n", ++ca, ans);
    }

    #ifndef ONLINE_JUDGE
        fprintf(stderr, "\n>> Runtime: %.10fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
    #endif

    return 0;
}