#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#define REP(i,s,n) for(int i=(int)(s);i<(int)(n);i++)

using namespace std;
typedef long long int ll;
typedef vector<int> VI;
typedef pair<int, int> PI;
const double EPS=1e-9;

const int N = 1010;

ll x[N], y[N];

ll dist[N][N];

int main(void){
  int n;
  cin >> n;
  REP(i, 0, n) {
    cin >> x[i] >> y[i];
  }
  double m = 0;
  REP(i, 0, n) {
    REP(j, 0, n) {
      ll sq = (x[j] - x[i]) * (x[j] - x[i]) + (y[j] - y[i]) * (y[j] - y[i]);
      sq = (sq + 99) / 100;
      dist[i][j] = ceil(sqrt((long double)sq));
    }
  }
  REP(k, 0, n) {
    REP(i, 0, n) {
      REP(j, 0, n) {
	dist[i][j] = min(dist[i][j], max(dist[i][k], dist[k][j]));
      }
    }
  }
  cout << 10 * dist[0][n-1] << endl;
}