N, p = map(int, input().split())
a = [0, 1]
mod = 10**9+7
for i in range(2, N):
    a.append((p*a[-1]+a[-2])%mod)
s = 0
res = 0
for i in range(N):
    s += a[i]
    s %= mod
    res += s*a[i]
    res %= mod
print(res)