#include "bits/stdc++.h"
using namespace std;
const auto start_time = std::chrono::high_resolution_clock::now();
void timecalculater(){
    #ifndef ONLINE_JUDGE
    auto end_time = std::chrono::high_resolution_clock::now();
    std::chrono::duration<double> diff = end_time-start_time;
    cerr<<"Time Taken : "<<diff.count()<<"\n";
    #endif
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void __print(int x) {cout << x;}
void __print(long x) {cout << x;}
void __print(long long x) {cout << x;}
void __print(unsigned x) {cout << x;}
void __print(unsigned long x) {cout << x;}
void __print(unsigned long long x) {cout << x;}
void __print(float x) {cout << x;}
void __print(double x) {cout << x;}
void __print(long double x) {cout << x;}
void __print(char x) {cout << '\'' << x << '\'';}
void __print(const char *x) {cout << '\"' << x << '\"';}
void __print(const string &x) {cout << '\"' << x << '\"';}
void __print(bool x) {cout << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cout << '{'; __print(x.first); cout << ','; __print(x.second); cout << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cout << '{'; for (auto &i: x) cout << (f++ ? "," : ""), __print(i); cout << "}";}
void _print() {cout << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cout << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define dbg(x...) cout << "[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif
#define fastio  cin.sync_with_stdio(0); cin.tie(0);cin.exceptions(cin.failbit);
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define repA(i, a, n) for(int  i = a; i <= (n); ++i)
#define all(x) x.begin(), x.end()
#define sz(x) (int) (x).size()
#define fill(a,v) memset(a, v, sizeof(a))
#define fst first
#define snd second
#define mp make_pair
#define pb push_back
#define endl '\n'
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long int> vll;
typedef vector<pii> vii;
ll p=1e9+7;
const int N=5e5+5;
ll fac[N];
ll invfac[N];
ll add(ll a,ll b){
    ll t=(a+b);
    if(t>=p)t%=p;
        return t;
}
ll sub(ll a,ll b){
    ll t=a-b+p;
    t=t%p;
    return t;
}
ll power(ll a,ll x){
    ll r=1;
    while(x!=0){
        if(x%2==1){
            r=r*a;r%=p;
        }
        a=a*a;a%=p;
        x=x/2;
    }
    return r;
}
ll mul(ll a,ll b){
    ll t=(a*b);
    if(t>=p)t%=p;
    return t;
}
ll divide(ll a, ll b){
    return mul(a,power(b,p-2));
}
ll npr(ll n, ll r){
    if(n< r)return 0;
    return mul(fac[n],invfac[n-r]);
}
ll ncr(ll n, ll r){
    if(n< r)return 0;
    return mul(fac[n],mul(invfac[n-r],invfac[r]));
}

int main() {
   
    fastio;
    int T=1;
    // cin>>T;
    fac[0]=1;
    for(ll i=1;i<N;i++){
        fac[i]=fac[i-1]*i;
        fac[i]%=p;
    }
    for(ll i=0;i<N;i++){
        invfac[i]=power(fac[i],p-2);
    }
    while(T--){     
        ll n,m;cin>>n>>m;
        ll ans=0;
        ans=mul(fac[n],ncr(m,n));
        ll temp=0;
        for(ll i=0;i<=n;i++){
            ll val=0;
            val=mul(ncr(n,i),mul(fac[n-i],ncr(m-i,n-i)));
            if(i%2==0){ 
                temp=add(temp,val);
            }
            else{
                temp=sub(temp,val);
            }
        }
        ans=mul(ans,temp);
        cout<<ans;
    }   
    timecalculater();
    return 0;   
} 

Measured memory_bytes: 11440