#include <stdio.h>
#include <string.h>
#include <iostream>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <map>
#include <string>
#include <algorithm>
#include <numeric>
#include <utility>
#include <cmath>

using namespace std;

typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;

const int iinf = 1 << 29;
const long long linf = 1ll << 61;

#define dump(x) cerr << #x << " : " << x << '\n'
#define MOD(x, y) (((y) + (x) % (y)) % (y))

int N;
int X[1001];
int Y[1001];
bool visit[1001];

bool C(int d)
{
	d *= 10;
	fill(visit, visit + 1001, false);
	queue<int> q;
	q.push(1);
	visit[1] = true;
	while (!q.empty()) {
		int v = q.front();
		q.pop();
		if (v == N) return true;
		for (int i = 1; i <= N; i++) {
			if (visit[i]) continue;
			ll x = X[v] - X[i];
			ll y = Y[v] - Y[i];
			ll dist = x * x + y * y;
			if (dist <= (ll)d * (ll)d) {
				visit[i] = true;
				q.push(i);
			}
		}
	}
	return false;
}

int main(int argc, char* argv[])
{
	scanf("%d", &N);
	for (int i = 1; i <= N; i++) {
		scanf("%d%d", &X[i], &Y[i]);
	}

	int l = 0, u = (int)(pow(10, 9) * pow(2, 0.5) / 10) + 1;
	while (l < u) {
		int mid = (l + u) / 2;
		if (C(mid)) u = mid;
		else l = mid + 1;
	}
	printf("%d\n", u * 10);

	return 0;
}