In a rectangular table
NxM , there is a checker in the upper left cell. In one move, it is allowed to move a checker to an adjacent cell either to the right or down (it is forbidden to move to the left and up). Count how many options there are to move the checker to the lower right cell.
Input
Two numbers
N and
M are entered - the dimensions of the table (1<=
N<=10, 1<=
M<=10).
Imprint
Output the desired number of options.
Examples