#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b;
	float c;
	cin>>a>>b;
	c=(3.1415926*a*a*2)+(3.1415926*2*a)*b;
	printf("%.2f",c);
}
/**************************************************************
	Problem: 1623
	User: panyuchen
	Language: C++
	Result: Wrong Answer
****************************************************************/