n, p = map(int, input().split())
mod = 10**9+7

if n == 1:
    print(0)
    exit()

A = [0]*n
A[0] = 0
A[1] = 1
for i in range(2, n):
    A[i] = p*A[i-1]+A[i-2]
    A[i] %= mod

from itertools import accumulate
C = list(accumulate(A))
ans = 0
for a, c in zip(A, C):
    ans += a*c
    ans %= mod
print(ans)