mod=10**9+7
n,p=map(int,input().split())
if n==1:
    print(0)
    exit()
ans=1
acum=1
fibs=[0,1,0]
for i in range(n-2):
    fibs[2]=p*fibs[1]+fibs[0]
    fibs[2]%=mod
    acum+=fibs[2]
    ans+=fibs[2]*(acum)
    ans%=mod
    fibs[0],fibs[1]=fibs[1],fibs[2]
print(ans)