
// The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked ‘Finish’ in the diagram below).

// How many possible unique paths are there?

// Note: A and B will be such that the resulting answer fits in a 32 bit signed integer.

// Example :

// Input : A = 2, B = 2
// Output : 2

// 2 possible routes : (0, 0) -> (0, 1) -> (1, 1) 
//               OR  : (0, 0) -> (1, 0) -> (1, 1)

