#include <bits/stdc++.h>
using namespace std;
#define TRACE(x) x
#define WATCH(x) TRACE( cout << #x" = " << x << endl)
#define PRINT(x) TRACE(printf(x))
#define WATCHR(a, b) TRACE( for(auto c = a; c != b;) cout << *(c++) << " "; cout << endl)
#define WATCHC(V) TRACE({cout << #V" = "; WATCHR(V.begin(), V.end()); } )
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()
#define mp make_pair
#define st first
#define nd second

using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using ld = long double;
using pll = pair<ll, ll>;
using vll = vector<ll>;
using pll = pair<ll, ll>;

void buff() { ios::sync_with_stdio( false ); cin.tie( nullptr ); }

constexpr ll MOD = 1e9 + 7;

inline ll pow_mod( ll a, ll b, ll mod = MOD) {
    ll res = 1; a %= mod; assert(b >= 0);
    for(;b;b>>=1) {
        if(b&1) res = (res * a) % mod;
        a = (a * a) % mod;
    }
    return res;
}
constexpr int ms = 1e6;
// End of template code!

struct mi {
	ll v; explicit operator ll() const { return v; }
	mi() { v = 0; }
	mi(ll _v) { 
		v = (-MOD < _v && _v < MOD) ? _v : _v % MOD;
		if (v < 0) v += MOD;
	}
	friend bool operator==(const mi& a, const mi& b) { 
		return a.v == b.v; }
	friend bool operator!=(const mi& a, const mi& b) { 
		return !(a == b); }
	friend bool operator<(const mi& a, const mi& b) { 
		return a.v < b.v; }
   
	mi& operator+=(const mi& m) { 
		if ((v += m.v) >= MOD) v -= MOD; 
		return *this; }
	mi& operator-=(const mi& m) { 
		if ((v -= m.v) < 0) v += MOD; 
		return *this; }
	mi& operator*=(const mi& m) { 
		v = v*m.v%MOD; return *this; }
	mi& operator/=(const mi& m) { return (*this) *= inv(m); }
	friend mi pow(mi a, ll p) {
		mi ans = 1; assert(p >= 0);
		for (; p; p /= 2, a *= a) if (p&1) ans *= a;
		return ans;
	}
	friend mi inv(const mi& a) { assert(a.v != 0); 
		return pow(a,MOD-2); }
		
	mi operator-() const { return mi(-v); }
	mi& operator++() { return *this += 1; }
	mi& operator--() { return *this -= 1; }
    mi operator++(int) { mi temp; temp.v = v++; return temp; }
    mi operator--(int) { mi temp; temp.v = v--; return temp; }
	friend mi operator+(mi a, const mi& b) { return a += b; }
	friend mi operator-(mi a, const mi& b) { return a -= b; }
	friend mi operator*(mi a, const mi& b) { return a *= b; }
	friend mi operator/(mi a, const mi& b) { return a /= b; }
    friend ostream& operator<<(ostream& os, const mi& m) {
        os << m.v; return os;
    }
    friend istream& operator>>(istream& is, mi& m) {
        ll x; is >> x;
        m.v = x;
        return is;
    }
};

mi fat[ms], invf[ms];

mi choose(mi n, mi k) {
    ll a = (ll) n;
    ll b = (ll) k;
    if(b > a) return 0;
    if(a < 0) return 0;
    if(b < 0) return 0;
    mi res = fat[a];
    res = res * invf[a - b];
    res = res * invf[b];
    return res;
}

int main() 
{
    buff();
    fat[0] = invf[0] = 1ll;
    for(int i = 1; i < ms; ++i)
    {
        fat[i] = (fat[i - 1] * i);
        invf[i] = inv(fat[i]); 
    }
    int n, m;
    cin >> n >> m;
    
    mi exc = 0ll;
    mi mul = 1ll;
    for(long long fix = 0; fix <= n; ++fix)
    {
        exc += mul * choose(n, fix) * choose(m - fix, n - fix) * fat[n - fix];
        mul = -mul;
    }
    
    cout << exc * choose(m, n) * fat[n] << '\n';

    return 0;
}



Measured memory_bytes: 19252