#include <stdio.h>
#include <vector>
#pragma warning(disable:4996) 

typedef long long ll;
const long long MOD = 1000000007;
using namespace std;

int main(int argc, char* argv[])
{
    int n,p;
    scanf("%d%d", &n, &p);

    ll sum=0;
    ll ans=0;
    vector<ll> a(n+1);
    int i;
    a[1]=0;
    a[2]=1;
    sum=1;
    ans=1;
    for(i=3; i<=n; i++) {
        a[i]=(p*a[i-1]+a[i-2])%MOD;

        sum=(sum+a[i])%MOD;
        ans=(ans+ sum*a[i])%MOD;
    }
    printf("%lld\n", ans);

    return 0;
}