#include <bits/stdc++.h>
using namespace std;
const int maxN = 100010, modP = 1000000007;
long long a, b, res;
int main() {
  scanf("%d%d", &a, &b);
  res = 0;
  for (int i = 1; i <= b - 1; ++i) {
    long long t = a, tmp, tmp1, tmp2;
    tmp = ((a + 1) * a) / 2;
    tmp = (tmp % modP);
    tmp = (tmp * i) % modP;
    tmp = (tmp * b) % modP;
    tmp2 = (a * i) % modP;
    tmp = (tmp + tmp2) % modP;
    res = (res + tmp) % modP;
  }
  cout << res;
  fclose(stdin);
  fclose(stdout);
}

### Prompt

Your task is to create a CPP solution to the following problem:

Dreamoon loves summing up something for no reason. One day he obtains two integers a and b occasionally. He wants to calculate the sum of all nice integers. Positive integer x is called nice if <image> and <image>, where k is some integer number in range [1, a].

By <image> we denote the quotient of integer division of x and y. By <image> we denote the remainder of integer division of x and y. You can read more about these operations here: http://goo.gl/AcsXhT.

The answer may be large, so please print its remainder modulo 1 000 000 007 (109 + 7). Can you compute it faster than Dreamoon?

Input

The single line of the input contains two integers a, b (1 ≤ a, b ≤ 107).

Output

Print a single integer representing the answer modulo 1 000 000 007 (109 + 7).

Examples

Input

1 1


Output

0


Input

2 2


Output

8

Note

For the first sample, there are no nice integers because <image> is always zero.

For the second sample, the set of nice integers is {3, 5}.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
const int maxN = 100010, modP = 1000000007;
long long a, b, res;
int main() {
  scanf("%d%d", &a, &b);
  res = 0;
  for (int i = 1; i <= b - 1; ++i) {
    long long t = a, tmp, tmp1, tmp2;
    tmp = ((a + 1) * a) / 2;
    tmp = (tmp % modP);
    tmp = (tmp * i) % modP;
    tmp = (tmp * b) % modP;
    tmp2 = (a * i) % modP;
    tmp = (tmp + tmp2) % modP;
    res = (res + tmp) % modP;
  }
  cout << res;
  fclose(stdin);
  fclose(stdout);
}

```