import java.util.*;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int p = sc.nextInt();
        long prepre = 0;
        long pre = 1;
        long sum = 1;
        long total = 1;
        if (n == 1) {
            System.out.println(0);
            return;
        } else if (n == 1) {
            System.out.println(1);
            return;
        }
        for (int i = 3; i <= n; i++) {
            long x = pre * p + prepre;
            x %= MOD;
            sum += x;
            sum %= MOD;
            total += sum * x;
            total %= MOD;
            prepre = pre;
            pre = x;
        }
        System.out.println(total);
    }
}