#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: panjinyan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/