#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define R cin>>
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<long double,long double> P;

long double d[1001][1001];
int main() {
  int n;
  cin >> n;
  P a[n];
  rep(i,n) cin >> a[i].F >> a[i].S;
  rep(i,n) {
    rep(j,n) d[i][j]=sqrt((a[i].F-a[j].F)*(a[i].F-a[j].F)+(a[i].S-a[j].S)*(a[i].S-a[j].S));
  }
  priority_queue<P,vector<P>,greater<P> > que;
  que.push(P(0,0));
  bool u[n];
  memset(u,false,sizeof(u));
  long double ans=0;
  while(!que.empty()) {
    P p=que.top();que.pop();
    long double c=p.F;
    int x=p.S;
    ans=max(ans,c);
    if(x==n-1) break;
    if(u[x]) continue;
    u[x]=true;
    rep(i,n) {
      if(u[i]) continue;
      que.push(P(d[x][i],i));
    }
  }
  ans/=10;
  ll z=ans=ceill(ans);
  z*=10;
  cout << z << endl;
  return 0;
}