def polymul(f,g):
    lf = len(f)
    lg = len(g)
    res = [0]*(lf+lg-1)
    for i in range(lf):
        for j in range(lg):
            res[i+j] += f[i]*g[j]
            res[i+j] %= MOD
    return res

MOD = 10**9+7
n,k = map(int,input().split())
a = [1]
for i in range(n):
    a = polymul(a,[1]*(i+1))
print(sum(a[:k+1])%MOD)