UVa 11549

#include<bits/stdc++.h>
using namespace std;

typedef unsigned long long int  ull;
typedef long long int      ll;
typedef vector<int>        vi;
typedef vector<ll>         vll;
typedef vector<vi>         vvi;
typedef pair<int,int >     pii;
typedef vector< pii >      vpii;
typedef set<int>           sti;

#define sc                 scanf
#define pf                 printf
#define sci(n)             scanf("%d",&n)
#define scii(n,m)          scanf("%d %d",&n,&m)
#define scl(n)             scanf("%lld",&n)
#define scd(n)             scanf("%lf",&n)
#define scs(s)             scanf("%s",s)
#define pfi(n)             printf("%d",n)
#define pfl(n)             printf("%lld",n)
#define pff(n)             cout<<n
#define line               printf("\n")
#define spc                printf(" ")
#define loop(i,x,y)        for(int i=int(x); i<=int(y); i++)
#define rloop(i,y,x)       for(int i=int(y); i>=int(x); i--)
#define cspf(i)            printf("Case %d: ", i)
#define vout(v)            for(int w=0;w<v.size();w++){if(w) cout<<' '; cout<<v[w];}
#define pb                 push_back
#define mp                 make_pair
#define ff                 first
#define ss                 second
#define all(v)             v.begin(),v.end()
#define rall(v)            v.rbegin(),v.rend()
#define read()             freopen("input.txt", "r", stdin)
#define write()            freopen("output.txt", "w", stdout)
#define fastIO()           ios_base::sync_with_stdio(false); cin.tie(NULL);
/// Constants
#define eps                1e-9
#define PI                 acos(-1.0)  // 3.1415926535897932
#define MAX                1000009

int digitcount(ll x,int cnt)
{
	if(x==0) return cnt;
	return digitcount(x/10,cnt+1);
}

ll SQR(ll x)
{
	return x*x;
}

int main()
{
	//read();
	//write();
	ll ten[20],k=1;
	loop(i,0,18){
		ten[i]=k;
		k*=10;
	}
	int t;
	sci(t);
	while(t--){
		int n;
		ll x;
		sci(n);
		scl(x);
		ll mx = x;
		map < ll, bool > flg;
		while(1){
			if(flg[x]) break;
			flg[x]=1;
			x = SQR(x);
			int d = digitcount(x,0);
			if(d>n){
				x = x/ten[d-n];
			}
			mx = max(x,mx);
		}
		pfl(mx);line;
	}
    return 0;
}