#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <bitset>
#include <set>
#include <deque>
#include <stack>
#include <atcoder/all>
#include <array>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)(n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < (t); ++i)
#define dsrep(i,t,s) for(int i = (t)-1; i >= (s); --i)
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define isin(x,l,r) ((l) <= (x) && (x) < (r))
int dx4[4]={1,0,-1,0};
int dy4[4]={0,-1,0,1};
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using P = pair<int,int>;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
// const ll mod = 998244353;
const ll mod = 1e9 + 7;

////////////////////////////////////////////
ll n, k;
ll mpow(ll x, ll p) {
  ll result = 1;
  for(; p>0; p >>= 1, x = x * x % mod) {
    if(p & 1) result = result * x % mod;
  }
  return result;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n >> k;
  ll t = mpow(n, k) - mpow(n - 1, k);
  while(t < 0) t += mod;
  t = t * n % mod;

  cout << t << endl;
}