#include <iostream>
#include <vector>
#include <atcoder/all>

using namespace std;
using namespace atcoder;

using mint=modint1000000007;

int main(){
    int n,p;
    cin>>n>>p;
    vector<mint> a(n+1,mint(0)),sum_a(n+1,mint(0));
    mint ans=mint(0);
    a[2]=mint(1);
    sum_a[2]=mint(1);

    for(int i=3;i<=n;i++){
        a[i]=p*a[i-1]+a[i-2];
        sum_a[i]=sum_a[i-1]+a[i];
    }
    for(int i=1;i<=n;i++){
        ans+=a[i]*sum_a[i];
    }
    cout<<ans.val()<<endl;

    return 0;
}