codeforces 559a//Gerald's Hexagon// Codeforces Round #313(Div. 1)

#pragma comment(linker,"/STACK:1024000000,1024000000") 
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<vector>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<set>
#include<algorithm>
#include <stack>
using namespace std;
const int SZ=1e7+10,INF=0x7FFFFFFF;
typedef long long lon;

int main()
{
    std::ios::sync_with_stdio(0);
    int a,b,c,d,e,f;
    cin>>a>>b>>c>>d>>e>>f;
    cout<<((a+f)*(a+b)+(c+d)*(d+e)-a*a-d*d)<<endl;
    return 0;
}