#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
#define REP(i, n) for(int i=0; i<n; i++)
#define REPi(i, a, b) for(int i=int(a); i<int(b); i++)
#define MEMS(a,b) memset(a,b,sizeof(a))
#define mp make_pair
#define MOD(a, m) ((a % m + m) % m)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll MOD = 1e9+7;

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

const int MAX_N = 110000;

ll fact[MAX_N+100];
ll frev[MAX_N+100];

ll rev(ll a, ll p){
    if(p == 0) return 1;
    ll tmp = rev(a, p/2);
    tmp = tmp * tmp % MOD;
    if(p % 2 == 1) tmp = tmp * a % MOD;
    return tmp;
}


void calc_fact(){
    fact[0] = frev[0] = 1;
    for(int i = 1; i <= MAX_N; i++){
        fact[i] = (fact[i-1] * i) % MOD;
        frev[i] = rev(fact[i], MOD-2);
    }
}


ll comb(int n, int k){
    if(n < 0 || k < 0 || n < k) return 0;
    if(n == 0 || k == 0) return 1;
    return fact[n] * frev[k] % MOD * frev[n-k] % MOD;
}

ll perm(int n, int k){
    if(n < 0 || k < 0 || n < k) return 0;
    if(n == 0 || k == 0) return 1;
    return fact[n] * frev[n-k] % MOD;
}

void prepare(){
    fact[0] = frev[0] = 1;
    for(int i = 1; i <= MAX_N; i++){
        fact[i] = (fact[i-1] * i) % MOD;
        frev[i] = rev(fact[i], MOD-2);
    }
}


int main(){
    ll N, M;
    cin >> N >> M;

    if(N < M){
        cout << 0 << endl;
        return 0;
    }

    prepare();

    ll ans = 0;
    for(int m = 0; m <= M; m++){
        /// m問は割り当てない
        ll num = comb(M, m) * mod_pow(M-m, N, MOD);
        if(m%2)
            ans += MOD - num;
        else
            ans += num;
        ans %= MOD;
    }

    cout << ans << endl;

    return 0;
}