Mod = 10**9+7
i,j = map(int,input().split())
if i==1 and j==1:
    print(1)
else:
    ret = [[1]*j]*i
    for x in range(1,i):
        for y in range(1,j):
            ret[x][y] = (ret[x-1][y]+ret[x][y-1])%Mod
    print(ret[i-1][j-1])