using namespace std;
#include <bits/stdc++.h>
#define BEGIN ios_base::sync_with_stdio(0);cin.tie(0);
#define END return EXIT_SUCCESS;
#define FOR(I,A,B) for(int (I)=(A);(I)<(B);++(I))
#define PI 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679 
int main()
{
	BEGIN
	cout<<PI<<endl;
	int C,A,B;
	cin>>C>>A>>B;
	cout<<setprecision(100)<<(PI*PI*(B+A)*(B-A)*(B-A)*C/4.0)<<endl;
	END
}