CF220D.Little Elephant and Triangle

The Little Elephant is playing with the Cartesian coordinates' system. Most of all he likes playing with integer points. The Little Elephant defines an integer point as a pair of integers (x; y), such that 0 ≤ x ≤ w and 0 ≤ y ≤ h. Thus, the Little Elephant knows only (w + 1)·(h + 1) distinct integer points.

The Little Elephant wants to paint a triangle with vertexes at integer points, the triangle's area must be a positive integer. For that, he needs to find the number of groups of three points that form such triangle. At that, the order of points in a group matters, that is, the group of three points (0;0), (0;2), (2;2) isn't equal to the group (0;2), (0;0), (2;2).

Help the Little Elephant to find the number of groups of three integer points that form a nondegenerate triangle with integer area.

小象正在玩笛卡尔坐标系。它最喜欢玩的是整点。小象将整点定义为一对整数 $(x, y)$，满足 $0 \le x \le w$ 且 $0 \le y \le h$。因此，小象只知道 $(w+1)\cdot(h+1)$ 个不同的整点。

小象想要绘制一个顶点均为整点的三角形，且该三角形的面积必须为正整数。为此，它需要找出能构成此类三角形的三元点组的数量。注意：点组中点的顺序是重要的，即三元点组 $(0,0),\ (0,2),\ (2,2)$ 与 $(0,2),\ (0,0),\ (2,2)$ 被视为不同。

请帮助小象找出能构成面积为正整数的非退化三角形的整点三元组的数量。

A single line contains two integers w and h (1 ≤ w, h ≤ 4000).

一行包含两个整数 $w$ 和 $h$（$1 \le w, h \le 4000$）。

In a single output line print an integer — the remainder of dividing the answer to the problem by 1000000007 (109 + 7).

在单行输出中打印一个整数——即该问题答案对 1000000007（$10^9 + 7$）取模的余数。