#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)

const int INF = 1e8;
const int MOD = 1e9+7;

typedef long long ll;

ll frac[100001];

ll modpow(ll x, ll n) {
    ll ret = 1;
    while (n) {
        if (n % 2) {
            ret *= x;
            ret %= MOD;
        }
        x *= x;
        x %= MOD;
        n /= 2;
    }
    return ret;
}

ll modinv(ll x) {
    return modpow(x,MOD-2);
}

int main(void) {
    int i, m;
    ll n;
    cin >> n >> m;

    if (n < m) {
        cout << 0 << endl;
        return 0;
    }
    frac[0] = 1;
    rep (i,100000) frac[i+1] = frac[i] * (i+1) % MOD;

    int ans = 0;
    rep (i,m) {
        int x = modpow(m-i,n) * frac[m] % MOD * modinv(frac[i]) % MOD * modinv(frac[m-i]) % MOD;
        if (i % 2 == 0)
            ans += x;
        else
            ans -= x;
        ans = (ans % MOD + MOD) % MOD;
    }
    cout << ans << endl;
    return 0;
}