#include<bits/stdc++.h> 
using namespace std;
typedef long long ll;
template<typename T1,typename T2> bool chmin(T1 &a,T2 b){if(a<=b)return 0; a=b; return 1;}
template<typename T1,typename T2> bool chmax(T1 &a,T2 b){if(a>=b)return 0; a=b; return 1;}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(20);

    ll mod = 1e9+7;
    ll p,k;
    cin>>p>>k;
    ll dp[k+1]={};
    dp[0]=1;
    ll now = 1;
    for(int i=0;i<k;i++){
        dp[i+1] = ((dp[i]*(p-1))%mod + now*2)%mod;
        now *= p*2;
        now %= mod;
    }
    cout << dp[k] << endl;
}