## Goal

Your city is a rectangular grid of buildings with streets joining them vertically and horizontally.

All the streets are one way: you can only go either south or east, but never north or west.

Your program has to compute the number of routes linking the North-West corner to the South-East one in an `M` x `N` city grid.

Be warned however that OneWay City is in fact a Megalopolisâ€”with all the headaches that it implies. Actually, the numbers can get so big that your program's output should only contain the first 1000 digits of the solution.
Input

Line 1: `M`, the number of west-east roads

Line 2: `N`, the number of north-south roads

Output

Number of ways leading from the North-West corner to the South-East one, truncated to the most significant 1000 digits.

Constraints

0 < `N`, `M` <= 5000