#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
const int MAX = 10000 + 5;
int n, x[MAX], y[MAX], sum, t;
double  ans = MAX,pi = 3.141592653589793238462643383279502884197369399357105;

int wh(int a, int b, int c, int d) {
	return pow(a-c,2)+pow(b-d,2);
}
int main() {
	cin >> n;
	for (int i = 1; i <=  n; ++i) {
		cin >> x[i];
		cin >> y[i];
	}
	for (int i = 1; i <= n; i++) {
		sum = 0;
		for (int j = 1; j <= n; ++j) {
			if (j != i) {
				t = wh(x[i], y[i], x[j], y[j]);
				sum = max(sum, t);
			}
		}
		ans = min(sum, (int)ans);
	}
	ans = ans * pi;
	printf("%.4lf", ans);
}