#include<iostream>
using namespace std;
int N;
long p,mod=1e9+7;
long a=1,b=0,s=1,ans=1;
main()
{
	cin>>N>>p;
	if(N==1)
	{
		cout<<0<<endl;
		return 0;
	}
	for(int i=2;i<N;i++)
	{
		long c=(a*p+b)%mod;
		(s+=c)%=mod;
		(ans+=s*c%mod)%=mod;
		b=a;a=c;
	}
	cout<<ans<<endl;
}