#include <cstdio>
#include <vector>
#include <algorithm>
#include <array>
#include <set>
#include <map>
#include <queue>
#include <tuple>
#include <unordered_set>
#include <unordered_map>
#include <functional>
#include <cassert>
#define repeat(i,n) for (int i = 0; (i) < (n); ++(i))
#define repeat_from(i,m,n) for (int i = (m); (i) < (n); ++(i))
typedef long long ll;
using namespace std;

const ll mod = 1e9+7;
ll powi(ll x, ll y, ll p) {
    assert (y >= 0);
    x = (x % p + p) % p;
    ll z = 1;
    for (ll i = 1; i <= y; i <<= 1) {
        if (y & i) z = z * x % p;
        x = x * x % p;
    }
    return z;
}
ll inv(ll x, ll p) {
    assert ((x % p + p) % p != 0);
    return powi(x, p-2, p);
}
ll choose(ll n, ll r) { // O(n) at first time, otherwise O(1)
    static vector<ll> fact(1,1);
    static vector<ll> ifact(1,1);
    if (fact.size() <= n) {
        int l = fact.size();
        fact.resize( n + 1);
        ifact.resize(n + 1);
        repeat_from (i,l,n+1) {
            fact[i]  = fact[i-1] * i % mod;
            ifact[i] = inv(fact[i], mod);
        }
    }
    r = min(r, n - r);
    return fact[n] * ifact[n-r] % mod * ifact[r] % mod;
}

int main() {
    ll n, m; scanf("%lld%lld", &n, &m);
    if (n < m) {
        printf("0\n");
    } else {
        ll ans = 0;
        repeat (i,m) {
            ans += (i % 2 ? -1 : 1) * powi(m-i, n, mod) * choose(m, i) % mod;
            ans %= mod;
        }
        ans = (ans % mod + mod) % mod;
        printf("%lld\n", ans);
    }
    return 0;
}