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#include <bits/stdc++.h>
#define PB push_back
#define ST first
#define ND second

//#pragma GCC optimize ("O3")
//#pragma GCC target("tune=native")

//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

using namespace std;
using ll = long long;
using pi = pair<int, int>;
using vi = vector<int>;

const int nax = 3000 + 10, mod = 1e9 + 7;
int n, m;
int dp[2][nax][2];

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> m;
	dp[0][0][1] = 1;
	dp[1][1][0] = m;
	for(int i = 2; i <= n; ++i) {
		for(int j = 0; j <= n; ++j) {
			dp[i&1][j][0] = 0;
		}
		int bt = i & 1;
		for(int j = 0; j <= n; ++j) {
			if(j > 0)
				dp[bt][j][0] = ((ll)dp[bt^1][j - 1][1] * (m - j+1)) % mod;
			dp[bt][j][0] = (dp[bt][j][0] + (ll)dp[bt^1][j][0] * (m - j)) % mod;
			dp[bt][j][1] = ((ll)(dp[bt^1][j][0] + dp[bt^1][j][1]) * j) % mod;
		}
	}
	int ans = 0;
	for(int i = 0; i <= n; ++i) {
		ans = (ans + dp[n&1][i][1]) % mod;
	}
	if(ans < 0) ans += mod;
	cout << ans;
}