#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <ctime>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
#include <numeric>
#include <string>

#define N_MAX 1000

using namespace std;

typedef long long ll;

int N;
ll X[N_MAX];
ll Y[N_MAX];
bool used[N_MAX];

// 長さ10*lのものさしを用いてP_0からP_(N-1)までつなげられるときに限りtrueを返す．
bool can_reach(ll l)
{
    fill(used, used + N, false);
    queue<int> q;
    q.push(0);
    used[0] = true;
    while (!q.empty()) {
        int p = q.front();
        q.pop();
        for (int i = 0; i < N; i++) {
            if (!used[i]) {
                ll dX = X[p] - X[i], dY = Y[p] - Y[i];
                if (dX * dX + dY * dY <= 100 * l * l) {
                    q.push(i);
                    used[i] = true;
                }
            }
        }
    }
    return used[N - 1];
}

int main(void)
{
    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> X[i] >> Y[i];
    }
    int low = 0, high = 400000000;
    // (low, high]の中に答えがある．
    while (high - low > 1) {
        int mid = (low + high) / 2;
        if (can_reach(mid)) {
            high = mid;
        } else {
            low = mid;
        }
    }
    cout << 10 * high << endl;
    return 0;
}