A. Gerald's Hexagon
链接：https://codeforces.com/problemset/problem/559/A
Gerald got a very curious hexagon for his birthday. The boy found out that all the angles of the hexagon are equal to 
He painted a few lines, parallel to the sides of the hexagon. The lines split the hexagon into regular triangles with sides of 1 centimeter. Now Gerald wonders how many triangles he has got. But there were so many of them that Gerald lost the track of his counting. Help the boy count the triangles.
Input
The first and the single line of the input contains 6 space-separated integers a1, a2, a3, a4, a5 and a6 (1 ≤ ai ≤ 1000) — the lengths of the sides of the hexagons in centimeters in the clockwise order. It is guaranteed that the hexagon with the indicated properties and the exactly such sides exists.
Output
Print a single integer — the number of triangles with the sides of one 1 centimeter, into which the hexagon is split.
Examples
input
Copy
1 1 1 1 1 1
output
Copy
6
input
Copy
1 2 1 2 1 2
output
Copy
13
Note
This is what Gerald's hexagon looks like in the first sample:
And that's what it looks like in the second sample:
Gerald got a very curious hexagon for his birthday. The boy found out that all the angles of the hexagon are equal to
He painted a few lines, parallel to the sides of the hexagon. The lines split the hexagon into regular triangles with sides of 1 centimeter. Now Gerald wonders how many triangles he has got. But there were so many of them that Gerald lost the track of his counting. Help the boy count the triangles.
Input
The first and the single line of the input contains 6 space-separated integers a1, a2, a3, a4, a5 and a6 (1 ≤ ai ≤ 1000) — the lengths of the sides of the hexagons in centimeters in the clockwise order. It is guaranteed that the hexagon with the indicated properties and the exactly such sides exists.
Output
Print a single integer — the number of triangles with the sides of one 1 centimeter, into which the hexagon is split.
Examples
input
Copy
1 1 1 1 1 1
output
Copy
6
input
Copy
1 2 1 2 1 2
output
Copy
13
Note
This is what Gerald's hexagon looks like in the first sample:
And that's what it looks like in the second sample:
代码：
#include<bits/stdc++.h>
using namespace std;
long long n,t,l,j,r,k,d,ans,max1=0,mod=1e9+7;
long long a[200005],b[200005];
map<long long,long long>m;
int main()
{
cin>>a[1]>>a[2]>>a[3]>>a[4]>>a[5]>>a[6];
k=a[1]+a[2]+a[3];
cout<<k*k-a[1]*a[1]-a[3]*a[3]-a[5]*a[5];
}