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#include <bits/stdc++.h>
#include <random>
#define ll long long int
#define pb push_back
#define st first
#define nd second
#define pii pair<int,int>
#define mp make_pair
#define pll pair<long long,long long>
#define ld long double
#define ull unsigned long long

using namespace std;

int n, m;
const int mod = 1e9 + 7;
const int nax = 3005;
ll dp[nax][nax][2];


void solve(){
    cin >> n >> m;
    dp[1][1][0] = m;
    for(int i=1;i<n;i++){
        for(int j=0;j<nax;j++){
            if(j > m) break;
            int endWays = j;
            int randomWays = m - j;
            dp[i + 1][j][1] += (dp[i][j][0] * endWays) % mod;
            if(dp[i + 1][j][1] >= mod) dp[i + 1][j][1] -= mod;

            dp[i + 1][j][0] += (dp[i][j][0] * randomWays) % mod;
            if(dp[i + 1][j][0] >= mod) dp[i + 1][j][0] -= mod;

            dp[i + 1][j][1] += (dp[i][j][1] * endWays) % mod;
            if(dp[i + 1][j][1] >= mod) dp[i + 1][j][1] -= mod;

            dp[i + 1][j + 1][0] += (dp[i][j][1] * randomWays) % mod;
            if(dp[i + 1][j + 1][0] >= mod) dp[i + 1][j + 1][0] -= mod;
        }
    }
    ll sum = 0;
    for(int i=0;i<nax;i++){
        sum += dp[n][i][1];
        sum %= mod;
    }
    cout << sum << "\n";
}

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

    int tt = 1;
    // cin >> tt;
    while(tt--) solve();

    return 0;
}