#include <bits/stdc++.h>
using namespace std;

const int N = 5e5 + 10;

struct Po {
	double x, y;
	Po(double X = 0.0, double Y = 0.0) {
		x = X, y = Y;
	}
};
Po operator -(Po a, Po b) {
	return Po(a.x - b.x, a.y - b.y); 
}
double operator *(Po a, Po b) {
	return a.x * b.y - a.y * b.x;
}
double dis(Po a, Po b) {
	Po d = a - b;
	return sqrt(d.x * d.x + d.y * d.y); 
}
double area(vector<Po> v) {
	double ret = 0.0;
	for (int i = 0; i < v.size(); ++i) ret += v[i] * v[(i + 1) % v.size()];
	return ret < 0.0 ? -ret / 2 : ret / 2;
}

int n;
Po p[N];

Po st[N], cvx[N];
int top = 0, l = 0;

int main() {
	cin >> n;
	for (int i = 1; i <= n; ++i) cin >> p[i].x >> p[i].y;
	sort(p + 1, p + n + 1, [&](Po a, Po b) { return a.x == b.x ? a.y < b.y : a.x < b.x;});
	
	st[top = 1] = p[1];
	for (int i = 2; i <= n; ++i) {
		while (top > 1 && (st[top] - st[top - 1]) * (p[i] - st[top - 1]) <= 0.0) --top;
		st[++top] = p[i];
	}
	for (int i = 1; i < top; ++i) cvx[++l] = st[i];
	st[top = 1] = p[n];
	for (int i = n - 1; ~i; --i) {
		while (top > 1 && (st[top] - st[top - 1]) * (p[i] - st[top - 1]) <= 0.0) --top;
		st[++top] = p[i];
	}
	for (int i = 1; i < top; ++i) cvx[++l] = st[i];
	
	n = l;
	for (int i = 1; i <= n; ++i) p[i] = cvx[i];
	
	double ans = 0;
	for (int i = 1, j = 3; i <= n; ++i) {
		while (area({p[i], p[i % n + 1], p[j % n + 1]}) > area({p[i], p[i % n + 1], p[j]})) j = j % n + 1;
		ans = max(ans, dis(p[i], p[j]));
		ans = max(ans, dis(p[i], p[j % n + 1]));
	}
	cout << fixed << setprecision(10) << ans << endl;

    return 0;
}