#include <iostream>
#include <cstring>
#include <cmath>
using namespace std;

double p, q, r;
double eps = 1e-7;

int main()
{
    int i, j, k;
    scanf( "%lf %lf %lf", &p, &q, &r );
    if ( abs( p-r ) > eps )
    {
        printf( "0\n" );
        return 0;
    }
    printf( "%.4lf\n", 2.0*p*p + 2.0*p*q );
    return 0;
}
