#include <bits/stdc++.h>
bool cmp(int x,int y){
    return x > y;
}
using namespace std;

int main() {
//Plese write your code in here , thak you so much!
long long int a,b,c;
cin>>a>>b>>c;
cout<<(a*b+a*c+b*c)*2;
	return 0;
}

哥你别来折磨我了