You are given an N x M size grid where N is the number of rows and M is the number of columns. Your task is to calculate in how many ways you can go from the upper-left corner to the bottom-right corner if you can only move down and to the right.
Input:
The input consists of two space-separated integers N and M (1 ≤ N, M ≤ 30).
Output:
Print out one integer - the answer to the given problem.