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

a, b = 0, 1
S = 0
SS = 0
tmp = 0
for i in range(N):
    S += a * SS % mod
    S %= mod
    a, b = b, (a + p * b) % mod
    SS += a % mod
    SS %= mod
print(S)