/* -*- coding: utf-8 -*-
 *
 * 1049.cc:  No.1049 Zero (Exhaust) - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MOD = 1000000007;

/* typedef */

typedef long long ll;

/* global variables */

inline void addmod(int &a, int b) { a = (a + b) % MOD; }

/* subroutines */

/* main */

int main() {
  int p, k;
  scanf("%d%d", &p, &k);

  int c0 = 1, c1 = 0;
  while (k--) {
    int nc0 = 0, nc1 = 0;

    // (1) add
    addmod(nc0, (c0 + (ll)c1 * (p - 1) % MOD) % MOD);
    addmod(nc1, (c0 + (ll)c1 * (p - 1) % MOD) % MOD);

    // (2) mul
    addmod(nc0, ((ll)c0 * p % MOD + (ll)c1 * (p - 1) % MOD) % MOD);
    addmod(nc1, (ll)c1 * (p - 1) % MOD);

    c0 = nc0, c1 = nc1;
  }

  printf("%d\n", c0);
  return 0;
}