MOD = 10 ** 9 + 7
N, p = map(int, input().split())
if N == 1:
    print(0)
    exit()
A = [0] * max(3,(N + 1))
A[2] = 1
suma = 1
ans = 1
for i in range(3, N + 1):
    A[i] = p * A[i - 1] + A[i - 2]
    A[i] %= MOD
    suma += A[i]
    ans += A[i] * suma
    ans %= MOD
print(ans)