n, p = map(int,input().split())
MOD = 10**9+7
if n == 1:
    print(0)
    exit(0)
elif n == 2:
    print(1)
    exit(0)
a = [0, 1]
for i in range(n-2):
    a.append((a[i+1]*p+a[i])%MOD)
s = sum(i**2 for i in a)
ans = (pow(sum(a), 2, MOD)+s)*pow(2, MOD-2, MOD)
ans %= MOD
print(ans)