#include <bits/stdc++.h>
using namespace std;
long mod = 0;
int getDublicatedPatterns(int cubes, int colors);
int main(){
    int n,m;
    cin >> n;
    cin >> m;
    //cout << "n " << n << " m " << m << endl;
    int numInkBottol = m;
    int numWanabePainted =n;
    long patterns = 1;
    mod = (long)pow(10,9)+7;
    if (numWanabePainted > numInkBottol) {

        patterns = getDublicatedPatterns(numWanabePainted,numInkBottol);

    }else{
        //インクの種類が十分多い
        //順番にインクのバケツにいれる。
        for (int i = numInkBottol; i > 0; i--){
            patterns = patterns * i;
            patterns = patterns % mod;
        }
    }
    cout << patterns << endl;
}
int getDublicatedPatterns(int cubes, int colors){
    int ret = 1;
    for(int i = cubes;i>0;i--){
        ret = ret*colors;
        ret = ret % mod;
    }
    //cout << "colors " <<colors << " ret " << ret << endl;
    if(colors > 0){
        ret = ret - (colors * getDublicatedPatterns(cubes,colors - 1));
    }
    //cout << "colors " <<colors << " ret " << ret << endl;

    return ret;
}