#include <cmath>
#include <iostream>
#include <climits>
#include <vector>

using namespace std;

double find_dist(int x1, int y1, int x2, int y2)
{
    return(sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)));

}

int main()
{
    int n, m;
    double d;
    cin >> n;
    double dist[n+1][n+1];

    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < n; j++)
        {
            dist[i][j] = INT_MAX-1;
        }
        dist[i][i] = 0;
    }

    int t1, t2, tw;
    vector< pair<int, int> > adj(n);
    for(int i = 0; i < n; i++)
    {
        cin >> t1 >> t2;
        adj[i].first = t1;
        adj[i].second = t2;
    }

    for(int i = 0; i < n-1; i++)
    {
        for(int j = i+1; j < n; j++)
        {
            //double d = abs(adj[i].first - adj[j].first) + abs(adj[i].second - adj[j].second);
            double dt = find_dist(adj[i].first, adj[i].second, adj[j].first, adj[j].second);
            //cout << dt << endl;
            if(dt <= 10.0)
                dist[i][j] = dist[j][i] = dt;
        }
    }

    for(int k = 0; k < n; k++)
    {
        for(int i = 0; i < n; i++)
        {
            for(int j = 0; j < n; j++)
            {
                d = dist[i][k] + dist[k][j];
                if(d < dist[i][j])
                {
                    dist[i][j] = d;
                }
            }
        }
    }

    int rez = -1;
   for(int i = 0; i < n; i++)
   {
       for(int j = 0; j < n; j++)
       {
           //cout << dist[i][j] << " ";
           if(dist[i][j] > rez)
                rez = dist[i][j];

       }
      // cout << endl;
   }

   if(rez == INT_MAX-1)
        cout << "NE"<< endl;
   else
    cout << rez << endl;
    return(0);
}