N, p = map(int, input().split())
mod = 1000000007

L = [0, 1]
S = 0
SS = 0
for i in range(N):
    S += L[i] * SS % mod
    S %= mod
    L.append((L[i] + p * L[i+1]) % mod)
    SS += L[i+1] % mod
    SS %= mod
print(S)