#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  vector<Int> x(n),y(n);
  for(Int i=0;i<n;i++) cin>>x[i]>>y[i];

  auto dist=
    [&](Int a,Int b){
      Int v=(x[a]-x[b])*(x[a]-x[b])+(y[a]-y[b])*(y[a]-y[b]);
      Int l=0,r=1e8;
      while(l+1<r){
        Int m=(l+r)>>1;
        if(m*m*100>=v) r=m;
        else l=m;
      }
      return r*10;
    };
  
  const Int INF = 1e15;
  vector<Int> dp(n,INF),used(n,0);
  dp[0]=0;  
  for(Int t=0;t<n;t++){
    Int v=-1;
    for(Int i=0;i<n;i++){
      if(used[i]) continue;
      if(v<0||dp[v]>dp[i]) v=i;
    }
    if(v<0) break;    
    used[v]=1;
    for(Int i=0;i<n;i++)
      chmin(dp[i],max(dp[v],dist(v,i)));
  }
  
  cout<<dp[n-1]<<endl;
  return 0;
}