Window

One wall of the house he lives in is a rectangle built from square bricks of size $1 \times 1$, stacked in $H$ rows and $W$ columns.

The house has no window and feels stuffy, so he wants to remove some bricks and open one. Because the hole becomes a window, the removed bricks must form a single solid rectangle.

He decides to think about mounting the window later and first to fix the spot the window will occupy, then remove every brick in that spot. He likes randomness, so he picks one of the $\frac{H(H+1)}{2} \times \frac{W(W+1)}{2}$ possible window positions uniformly at random and removes every brick in it. Removing one brick costs 9 won.

Write a program that prints the expected cost of removing the bricks.

The first line contains two natural numbers $H$ and $W$, the size of the wall, separated by one space. ($1 \le H, W \le 10^{18}$)

Print the expected cost of removing the bricks. For exact judging, write the answer as an irreducible fraction $\frac{a}{b}$ and print $a \times b^{-1}$ modulo 1,000,000,007 instead. Here $b^{-1}$ is the modular multiplicative inverse of $b$. The answer exists for every possible input of this problem.