from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N,p = map(int,input().split())
mod = 10**9 + 7
if N==1:
    print(0)
    exit()
a = [0]*(N+1)
a[2]=1
ans = 0
S = 0

ans = 1
S = 1
for i in range(3,N+1):
    a[i]=(p*a[i-1]+a[i-2])%mod
    S += a[i]
    ans += S*a[i]
    ans %= mod
    S %= mod
print(ans)