#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll MOD = 1e9 + 7;

ll f[100010], f_inv[100010];

ll modpow(ll x, ll n) {
	ll res = 1;
	while (n > 0) {
		if (n & 1) res = res * x % MOD;
		x = x * x % MOD;
		n >>= 1;
	}
	return res;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	ll n, m;
	cin >> n >> m;
	if (n < m) {
		cout << 0 << endl;
		return 0;
	}
	f[0] = 1;
	for (int i = 1; i <= m; i++) {
		f[i] = f[i - 1] * i % MOD;
	}
	f_inv[m] = modpow(f[m], MOD - 2);
	for (int i = m; i > 0; i--) {
		f_inv[i - 1] = f_inv[i] * i % MOD;
	}
	ll ans = 0;
	for (int i = 0; i < m; i++) {
		ll tmp = f[m] * f_inv[i] % MOD * f_inv[m - i] % MOD;
		(tmp *= modpow(m - i, n)) %= MOD;
		if (i % 2 == 0) {
			(ans += tmp) %= MOD;
		} else {
			(ans += MOD - tmp) %= MOD;
		}
	}
	cout << ans << endl;
	return 0;
}