N, K = map(int, input().split())
mod = 10 ** 9 + 7

n = 202020

fact = [1] * (n + 1)
invfact = [1] * (n + 1)
for i in range(1, n):
    fact[i + 1] = ((i+1) * fact[i]) % mod
invfact[n] = pow(fact[n], mod - 2, mod)
for i in range(n - 1, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % mod
    
now = K + N - 1
val = 1
for i in range(N):
    val *= now - i
    val %= mod
    
ans = 0
inv = pow(N, mod - 2, mod)
for m in range(N):
    ans += inv * invfact[m] * invfact[N - 1 - m] * val
    ans %= mod
    val *= pow(now, mod - 2, mod)
    val *= now - N
    val %= mod
    now -= 1
    
print(ans)