Robot Walle is located in the coordinate plane at (0,0). Calculate the number of ways in which the Walle can get to the position (ex,ey) provided that the position (x,y) can be reached only from the point (x−1,y) or (x,y−1), and must hold the conditions x≥y and x⋅y is even.
Two positive integers ex,ey (1≤ex,ey≤100).
Print the number of ways modulo 109+7.