#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <map>
#include <iomanip>

#define pb push_back
#define fst first
#define snd second

#define forn(i,n) forr(i,0,n)
#define forr(i,x,n) for(int i=(x); i<int(n); i++)

using namespace std;

typedef unsigned long long ll;

const ll MAXN = 200005;
const ll INF = 1e18;
const ll MOD = 1e9 + 7;

struct pt {
	double x, y;
	int id;

    pt(double x=0, double y=0, int id=0):x(x),y(y),id(id){}
    pt operator-(pt a){return pt(x-a.x, y-a.y);}
	double norm(){return sqrt(x*x+y*y);}
};
double dist(pt a, pt b){return (b-a).norm();}

bool cmp (pt a, pt b) {
	return a.x <b.x || a.x == b.x && a.y <b.y;
}

bool cw (pt a, pt b, pt c) {
	return a.x * (b.y-c.y) + b.x * (c.y-a.y) + c.x * (a.y-b.y) <0;
}

bool ccw (pt a, pt b, pt c) {
	return a.x * (b.y-c.y) + b.x * (c.y-a.y) + c.x * (a.y-b.y)> 0;
}

void convex_hull (vector <pt> & a) {
	if (a.size () == 1) return;
	sort (a.begin (), a.end (), & cmp);
	pt p1 = a [0], p2 = a.back ();
	vector <pt> up, down;
	up.push_back (p1);
	down.push_back (p1);
	for (size_t i = 1; i <a.size (); ++ i) {
		if (i == a.size () - 1 || cw (p1, a [i], p2)) {
			while (up.size () >= 2 &&! cw (up [up.size () - 2], up [up.size () - 1], a [i]))
				up.pop_back ();
			up.push_back (a [i]);
		}
		if (i == a.size () - 1 || ccw (p1, a [i], p2)) {
			while (down.size () >= 2 &&! ccw (down [down.size () - 2], down [down.size () - 1], a [i]))
				down.pop_back ();
			down.push_back (a [i]);
		}
	}
	a.clear ();
	for (size_t i = 0; i <up.size (); ++ i)
		a.push_back (up [i]);
	for (size_t i = down.size () - 2; i> 0; --i)
		a.push_back (down [i]);
}

int N;
vector<pt> V;

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);

    cin >> N;
    forn(i,N){
        double a, b;
        cin >> a >> b;
        V.push_back({a,b,i});
    }

    convex_hull(V);

    double perim = 0;
    forn(i, V.size()) perim += dist(V[i], V[(i+1)%V.size()]);

    cout << fixed << setprecision(0) << perim << '\n';

    return 0;
}