#ifndef LOCAL
#include <bits/stdc++.h>

using namespace std;

#define debug(...) (void(0))
#else
#include "algo/debug.h"
#endif

#include <atcoder/modint>
using mint = atcoder::modint1000000007;

void solve() {
    int P, K;
    cin >> P >> K;
    mint ans = 1;
    mint oth = 0;
    for (int i = 0; i < K; i++) {
        mint na = 0, no = 0;
        na += oth * (P - 1) + ans;
        no += ans + (oth) * (P - 1);
        na += P * ans + oth * (P - 1);
        no += oth * (P - 1);
        ans = na;
        oth = no;
    }
    cout << ans.val() << endl;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int tt = 1;
    // std::cin >> tt;
    while (tt--) {
        solve();
    }
}