The boy Petya has an ant farm. The farm has a rectangular area consisting of NxM squares. There is a hole in the lower right square of this area, thanks to which you can escape from the farm. Every day, the next ant starts its journey from the upper left cell. Then it moves to the next cell either to the right or down (it does not move left and up maybe), and moves like this until it reaches the bottom right cell. Then he climbs out. Each ant moves in its own unique way (i.e. no ant repeats any path of another). If the ant cannot follow its unique path, then it stays on the farm. Count how many ants will run away from the farm and settle in Petya's room.
Input
Enter two numbers N and M -table sizes (
\(1<=N<=10\),
\(1<=M<=10\)).
Output
Output the desired number of ways.
Note
Under these restrictions, the number of ways is included in the type
Longint.
Examples