#include<cstdio>

 #include<iostream>

 #include<algorithm>

 #include<cstring>

 #include<cmath>

 #include<queue>

 #include<map>

 using namespace std;

 #define MOD 1000000007

 const int INF=0x3f3f3f3f;

 const double eps=1e-;

 typedef long long ll;

 #define cl(a) memset(a,0,sizeof(a))

 #define ts printf("*****\n");

 const int MAXN=;

 int n,m,tt;

 int a[MAXN];

 int main()

 {

     int i,j,k;

     #ifndef ONLINE_JUDGE

     freopen("1.in","r",stdin);

     #endif

     int a1,a2,a3,a4,a5,a6;

     while(~scanf("%d%d%d%d%d%d",&a1,&a2,&a3,&a4,&a5,&a6))

     {

         printf("%d\n",(a1+a2+a3)*(a1+a2+a3)-a5*a5-a3*a3-a1*a1);

     }

 }