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/*
	Zadanie: 
	Autor: Tomasz Kwiatkowski
*/

#include <bits/stdc++.h>

#define fi first
#define se second
#define pb push_back

using namespace std;
typedef long long ll;

const int MAXN = 1000*1000 + 7;
const int MOD = 1000*1000*1000 + 7;

int n, m;

bool ok(vector<int>& v)
{
	vector<bool> dp(n + 1);
	dp[0] = true;
	for (int i = 1; i <= n; ++i) {
		for (int j = 0; j < i - 1; ++j) {
			if (dp[j] && v[j] == v[i - 1])
				dp[i] = true;
		}
	}
	return dp[n];
}

int solve(vector<int> v, int ind)
{
	if (v.size() == n)
		return ok(v);

	int ans = 0;
	v.pb(0);
	for (int i = 1; i <= m; ++i) {
		v[ind] = i;
		ans += solve(v, ind + 1);
		ans %= MOD;
	}
	return ans;
}

int main()
{
	ios_base::sync_with_stdio(0), cin.tie(0);
	
	cin >> n >> m;

	cout << solve({}, 0) % MOD << '\n';
	return 0;
}