#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using Modint = atcoder::modint1000000007;


int main(){
    int H, W;
    cin >> H >> W;
    vector<Modint> fac(H + 1), inv(H + 1);
    fac[0] = 1;
    for(int i = 1; i <= H; i++) fac[i] = fac[i - 1] * Modint::raw(i);
    inv[H] = fac[H].inv();
    for(int i = H; i; i--) inv[i - 1] = inv[i] * Modint::raw(i);
    auto binom = [&](int n, int r){ return fac[n] * inv[r] * inv[n - r]; };
    Modint ans = 0;
    Modint x = 1;
    for(int h = 0; h <= H; h++){
        if((h ^ H) & 1) ans -= (x - 1).pow(W) * binom(H, h);
        else ans += (x - 1).pow(W) * binom(H, h);
        x += x;
    }
    cout << ans.val() << endl;
}