#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>

using namespace std;
 
struct UnionFind {
    vector<long long> par;
    vector<long long> siz;

    UnionFind(long long N) : par(N), siz(N) {
        for(long long i = 0; i < N; i++){
            par[i] = i;
            siz[i] = 1;
        }   
    }   
 
    long long root(long long x) {
        if (par[x] == x) return x;
        return par[x] = root(par[x]);
    }   
 
    long long unite(long long x, long long y) {
        long long rx = root(x);
        long long ry = root(y);
        if (rx == ry) return rx; 
        if (siz[rx] > siz[ry]) swap(rx, ry);
        par[rx] = ry; 
        siz[ry] += siz[rx];
        return ry; 
    }   
 
    bool same(long long x, long long y) {
        long long rx = root(x);
        long long ry = root(y);
        return rx == ry; 
    }   
 
    long long size(long long x){ 
        return siz[root(x)];
    }   
};

int main(){
 
    long long N;
    long double mx=0;
    cin >> N;
    if (N == 0){
        cout << 1 << endl;
        return 0;
    }

    vector<long long> X(N), Y(N);
    UnionFind tree(N);
    for (int i=0; i<N; i++) cin >> X[i] >> Y[i];

    auto d = [&](int i, int j){return (X[i]-X[j])*(X[i]-X[j]) + (Y[i]-Y[j])*(Y[i]-Y[j]);};

    for (int i=0; i<N; i++){
        for (int j=i+1; j<N; j++){
            if (d(i, j) <= 100) tree.unite(i, j);
        }
    }
 
    for (int i=0; i<N; i++){
        for (int j=i+1; j<N; j++){
            if (tree.same(i, j)) mx = max(mx, sqrt((long double)d(i, j)));
        }
    }
 
    cout << setprecision(18) << mx+2 << endl;
 
    return 0;
}