#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <ctime>
#define x first
#define y second
using namespace std;

typedef long long LL;
typedef pair<double, double> PDD;

const int N = 5e4 + 5;
const double PI = acos(-1);
int n;

PDD a[N];

double ans;

void inline work(int i, int j) {
    double dx = a[i].x - a[j].x, dy = a[i].y - a[j].y;
    ans = max(ans, sqrt((LL)(dx * dx + dy * dy)));
}

PDD inline rotate(PDD a, double x) { return (PDD) { cos(x) * a.x + sin(x) * a.y, -sin(x) * a.x + cos(x) * a.y }; }
double inline rd() {
    return ((double)rand() / RAND_MAX);
}

int main() {
    double s = clock();
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%lf%lf", &a[i].x, &a[i].y);
    int t = sqrt(n);
    while ((clock() - s) / CLOCKS_PER_SEC < 0.4) {
        double p = PI * 2 * rd();
        for (int i = 1; i <= n; i++) a[i] = rotate(a[i], p);
        sort(a + 1, a + 1 + n);
        for (int i = 1; i <= t; i++)
            for (int j = n; j >= n - t; j--) work(i, j);
    }

    printf("%.9lf\n", ans);
}
/*
作者：墨染空
链接：https://www.acwing.com/activity/content/code/content/811721/
来源：AcWing
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
*/