#include<iostream>
#include<queue>
#include<algorithm>
#include<map>
#include<vector>
#include<functional>

using namespace std;

typedef long long LL;
typedef pair<LL, LL> PI;
typedef vector<PI> VP;
typedef pair<LL, int> PL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;


#define x(_v) _v.first
#define y(_v) _v.second
#define cost(_v) _v.first
#define to(_v) _v.second
#define mp(_x,_y) make_pair(_x,_y)
#define dist(_v,_u) (x(_v)-x(_u))*(x(_v)-x(_u))+(y(_v)-y(_u))*(y(_v)-y(_u))
const LL INF = 2*(LL)1e9;
int main(){
	int N;
	cin >> N;
	VP p(N);
	for (auto& v: p){
		cin >> x(v) >> y(v);
	}
	VVLL edge(N, VLL(N));
	for (int i = 0; i < N; i++){
		for (int j = 0; j < N; j++){
			edge[i][j] = dist(p[i], p[j]);
		}
	}
	priority_queue<PL,vector<PL>,greater<PL>> que;
	vector<LL> used(N, -1);
	que.push(mp(0, 0));

	while (que.empty() == false){
		auto v = que.top(); que.pop();
		if (used[to(v)]>=0)continue;
		used[to(v)] = cost(v);
		for (int i = 0; i < N; i++){
			if (to(v)!=i&&used[i]==-1){
				que.push(mp(max(used[to(v)],edge[to(v)][i]), i));
			}
		}
	}
	LL res = used[N - 1];
	LL l = 0;
	LL h = INF;
	while (h - l > 1){
		LL m = ((l + h) / 2)*10;
		if (res <= m*m)h = m / 10;
		else l = m / 10;
	}
	cout << h * 10 << endl;


	return 0;
}