#include <iostream>
#include <vector>
#include <queue>
#include <cmath>
using namespace std;
const double EPS = 1e-8;
struct UnionFind {
  int n;
  vector<int> par;
  vector<int> size_;
  UnionFind(int n_) : n(n_), par((size_t)n_), size_((size_t)n_,1){
    for(int i = 0; n > i; i++)par[i] = i;
  }

  int root(int x){
    if(par[x] == x)return x;
    return par[x] = root(par[x]);
  }

  void unite(int a,int b){
    int ra = root(a);
    int rb = root(b);
    if(ra==rb)return;
    if(size(ra) > size(rb)) swap(ra,rb);
    par[ra] = rb;
    size_[rb] += size_[ra];
  }

  bool same(int a, int b){
    return root(a) == root(b);
  }

  int size(int a){
    return size_[root(a)];
  }
  void debug(){
    for(int i = 0; n > i; i++){
      cout << size_[root(i)] << " ";
    }
    cout << endl;

    return;
  }
};

struct d{
  int x,y;
  long long dist;
  bool operator<(const d &a)const{
    if(dist == a.dist){
      if(x == a.x)return y < a.y;
      return x < a.x;
    }
    return dist < a.dist;
  }
  bool operator==(const d &a)const{
    return dist==a.dist && x==a.x && y == a.y;
  }
  bool operator>(const d &a)const{
    return !((*this)<a ||(*this)==a);
  }
};

int main(){
  int n;cin>>n;
  vector<pair<long long,long long>> A(n);
  for(int i = 0; n > i; i++){
    cin>>A[i].first>>A[i].second;
  }
  priority_queue<d,vector<d>,greater<d>> B;
  for(int i = 0; n > i; i++){
    for(int j = i+1; n > j; j++){
      B.push({i,j,(A[i].first-A[j].first)*(A[i].first-A[j].first)+(A[i].second-A[j].second)*(A[i].second-A[j].second)});
    }
  }
  UnionFind C(n);
  while(C.size(0) != n){
    auto x = B.top();B.pop();
    C.unite(x.x,x.y);
    if(C.root(0) == C.root(n-1)){
      long long mn = 0;
      long long mx = 200000000;
      while(mx-mn > 1){
        long long ce = (mx+mn)/2;
        if(ce*ce*100 >= x.dist){
          mx = ce;
        }else{
          mn = ce;
        }
      }
      cout << mx*10 << endl;
      break;
    }
  }
}