#include<bits/stdc++.h>

using namespace std;
using ll = long long int;
using lc = complex<double>;

int main(void) {
    constexpr ll MOD = 1e9 + 7;
    constexpr double PI = acos(-1);
    cout << fixed << setprecision(32);
    cin.tie(0); ios::sync_with_stdio(false);

    ll p, k;
    cin >> p >> k;

    ll z = 1, nz = 0;
    while(k--) {
        ll pz = z, pnz = nz;
        (z = 2*(pnz+pz) + pz*(p-1)) %= MOD;
        (nz = (2*pnz+pz)*(p-1)) %= MOD;
    }
    cout << z << endl;
}