x = input().split(" ") n, m = int(x[0]), int(x[1]) dp = [[0] * (m + 1) for _ in range(n + 1)] # 初始化二维数组 dp[1][1] = 1 for i in range(2, n + 1): dp[i][1] = dp[i - 1][1] for i in range(2, m + 1): dp[1][i] = dp[1][i - 1] for i in range(2, n + 1): for j in range(2, m + 1): dp[i][j] = dp[i - 1][j] + dp[i][j - 1] dp[i][j] = int(dp[i][j]%(1e9 + 7)) print(int(dp[n][m] % (1e9 + 7)))