题解 | #走方格的方案数#

nm = list(map(int,input().split()))
n, m = nm[0], nm[1]
path = 0

def bfs(pl, pc):
    # print(pl,pc)
    if pl != n or pc != m:
        if pl < n and pc < m:
            return bfs(pl+1, pc) + bfs(pl, pc+1)
        elif pl == n and pc < m:
            return bfs(pl, pc+1)
        elif pl < n and pc == m:
            return bfs(pl+1, pc)
    else:
        return 1

print(bfs(0,0))
# matrix = []
# for l in range(n+1):
#     line = []
#     for c in range(m+1):
#         point = '(' + str(l) + ',' + str(c) + ')'
#         line.append(point)
#     matrix.append(line)
# print(matrix)