#include<bits/stdc++.h>
using namespace std;
const double pi=3.1415926535;
struct cmd{
	int x;
	int y;
}a[1005];
int n;
double maxx=0,minn=1e9;
double dis(cmd n1,cmd n2){
	double a=abs(n1.x-n2.x);
	double b=abs(n1.y-n2.y);
	return sqrt(a*a+b*b);
}
int main(){
	cin>>n;
	for(int i = 0;i<n;i++){
		cin>>a[i].x>>a[i].y;
	}
	for(int i = 0;i<n;i++){
		for(int j = 0;j<n;j++){
			double tmp=dis(a[i],a[j]);
			maxx=max(tmp,maxx);
		}
		minn=min(minn,maxx);
	}
	printf("%.4lf",minn*minn*pi);
	return 0;
}