Ride me, the big turtle!

The turtle is located in the upper-left corner $(1,1)$ of the table of size $1012421\times 1099921$. The animal is able only to walk one cell down or one cell right.

In how many ways the turtle can reach the cell $(n,m)$?

Input

Two integers $n$ and $m$ $(1\le n,m\le 50)$ are given in one line.

Output

Print one line – the number of ways to reach the cell $(n,m)$.

Examples