#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
#define rep(i, n) for (ll i = 0; i < (ll) (n); i++)
using mint =modint1000000007;
using vm = vector<mint>;
int main() {
    ll P,K;
    cin>>P>>K;
    vm D(K+1,0),E(K+1,0);
    D[0]=1;
    rep(i,K){
        E[i+1]=(D[i]+2*E[i])*(P-1);
        D[i+1]=2*E[i]+D[i]*(P+1);
    }
    cout<<D[K].val()<<endl;
}