#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,s;
	cin>>a>>b>>c;
	if(a<c)swap(a,c);
	if(a<b)swap(a,b);
	if(b<c)swap(c,b);
	s=a*b+b*c*2+a*c*2;
	cout<<s; 
	return 0;
}

/**************************************************************
	Problem: 1340
	User: tangkaixuan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/