cf 559a **

题意：给一个六边形，求小三角形个数

 #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);
     }
 }