题解 | #走方格的方案数# #动态规划# #递归#

# 走方格的方案数
n, m = map(int,input().split())
dp = [[1 for _ in range(n+1)] for _ in range(m+1)]
#动态规划的方法
for i in range(1,m+1):
    for j in range(1,n+1):
        dp[i][j] = dp[i-1][j]+dp[i][j-1]
print(dp[m][n])

# 递归的方法
def func(x,y):
    if x < 0 or y < 0:
        return 0
    elif x == 0 or y == 0:
        return 1
    else:
        return func(x-1, y)+func(x, y-1)
 
while True:
    try:
        n, m = map(int, input().split())
        res = func(n, m)
        print(res)
    except:
        break