题解 | #走方格的方案数#

#动态规划
while 1:
    try:
        n,m=map(int,input().split(' '))
        dp=[[1 for i in range(n+1)] for j in range(m+1)]
        # print(dp) #[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
        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])
    except:
        break



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