#include <cstdio>
#include <queue>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstring>

using namespace std;

int main(){
   int N;
   cin >> N;
   pair<long long ,long long> points[N];
   for( int i = 0 ; i <N; i++ ){
      cin >> points[i].first>> points[i].second;
   }
   vector<pair<long long,int> > edge[N];
   for( int i = 0; i<N;i++){
      for( int j = 0 ; j <N ; j++ ){
         if( i==j ) continue;
         long long dx=points[i].first-points[j].first;
         long long dy=points[i].second-points[j].second;
         edge[i].push_back( make_pair(dx*dx+dy*dy,j) );
      }
   }
   for(int i=0;i<N;i++){
      sort(edge[i].begin(),edge[i].end());
   }
   long long left = 0;
   long long right = 200000000;
   while( left+1 < right){
      long long mid=(left+right)/2;
      long long dist = mid*10;
      bool arrived[N];
      memset(arrived,false,sizeof(arrived));
      stack<int> q;
      q.push(0);
      arrived[0]=true;
      bool ok = false;
      while(ok==false&&!q.empty()){
         int cur = q.top();
         q.pop();
         for( int i = 0; i <N-1 ; i++ ){
            if( edge[cur][i].first > dist*dist ) break;
            if( arrived[edge[cur][i].second] ) continue;
            if( edge[cur][i].second == N-1){
               ok=true;
               break;
            }
            arrived[edge[cur][i].second]=true;
            q.push(edge[cur][i].second);
         }     
      }
      if( ok ){
         right = mid;
      }
      else{
         left = mid;
      }
   }
   cout << right*10;
   return 0;
}