#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b;
    cin>>a>>b;
    printf("%.2f",(3.1415926*a*a)*2+(3.1415926*2*a)*b*1.0);
}
/**************************************************************
	Problem: 1623
	User: lijinkai
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/