盛日辉的博客

FileInput = False

if FileInput:
    sys.stdin = open('flower.in', 'r')
    sys.stdout = open('flower.out', 'w')

# n酒店，m花
n, m = map(int, input().split())
dp = [[[0 for k in range(m + 1)] for j in range(m + 1)] for i in range(n + 1)]
# dp[i][j][k] 遇到i个酒店j个花后剩余k酒量的方案数
dp[0][0][2] = 1
# dp[1][0][4] = 1
# dp[0][1][1] = 1
# dp[0][2][0] = 1

for i in range(0, n + 1):
    for j in range(0, m + 1):
        for k in range(m + 1):
            if j == m and i != n:  # 不能没花了但酒店还有
                continue
            if not k & 1 and i > 0:  # 现在这一个是酒店，i减1，k是一半
                dp[i][j][k] += dp[i - 1][j][k // 2]
            if k != m and j > 0:
                dp[i][j][k] += dp[i][j - 1][k + 1]

print(dp[n][m][0] % 1000000007)