#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
long long mod = 1e9 + 7;
typedef long long ll;
int main(){
    ll P, K;
    cin >> P >> K;
    ll ans0 = P + 1;
    ll size = 2* P;
    for(int i = 1; i < K; i++){
        ans0 = (ans0 * (P - 1) + 2 * size) % mod;
        size = (2*size * P) % mod;
    }
    cout << ans0 << endl;
}