#include <bits/stdc++.h>
using namespace std;

#define watch(x) cerr << (#x) << ": " << (x) << endl

typedef long long LL;

const int N = 500009, MOD = 1000000007;

struct mint {
    int val;
 
    mint(int v = 0) {
        val = v % MOD;
        if(val < 0) val += MOD;
    }
 
    static int mod_inv(int a, int m = MOD) {
        int g = m, r = a, x = 0, y = 1;
 
        while (r != 0) {
            int q = g / r;
            g %= r; swap(g, r);
            x -= q * y; swap(x, y);
        }
 
        return x < 0 ? x + m : x;
    }
 
    explicit operator int() const {
        return val;
    }
 
    mint& operator+=(const mint &other) {
        val += other.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
 
    mint& operator-=(const mint &other) {
        val -= other.val;
        if (val < 0) val += MOD;
        return *this;
    }
 
    mint& operator*=(const mint &other) {
        val = ((uint64_t) val*other.val)%MOD;
        return *this;
    }
 
    mint& operator/=(const mint &other) {
        return *this *= other.inv();
    }
 
    friend mint operator+(const mint &a, const mint &b) { return mint(a) += b; }
    friend mint operator-(const mint &a, const mint &b) { return mint(a) -= b; }
    friend mint operator*(const mint &a, const mint &b) { return mint(a) *= b; }
    friend mint operator/(const mint &a, const mint &b) { return mint(a) /= b; }
 
    mint& operator++() {
        val = val == MOD - 1 ? 0 : val + 1;
        return *this;
    }
 
    mint& operator--() {
        val = val == 0 ? MOD - 1 : val - 1;
        return *this;
    }
 
    mint operator++(int32_t) { mint before = *this; ++*this; return before; }
    mint operator--(int32_t) { mint before = *this; --*this; return before; }
 
    mint operator-() const {
        return val == 0 ? 0 : MOD - val;
    }
 
    bool operator==(const mint &other) const { return val == other.val; }
    bool operator!=(const mint &other) const { return val != other.val; }
 
    mint inv() const {
        return mod_inv(val);
    }
 
    mint pow(int p) const {
        mint a = *this, result = 1;
 
        while (p > 0) {
            if (p & 1)
                result *= a;
 
            a *= a;
            p >>= 1;
        }
 
        return result;
    }
 
    friend ostream& operator<<(ostream &stream, const mint &m) {
        return stream << m.val;
    }
};

int n, m;

int sz;
mint f[N];
mint fac(int i) {
    if(sz == 0) {
        f[0] = 1;
        sz++;
    }

    while(sz <= i) {
        f[sz] = f[sz-1]*sz;
        sz++;
    }

    return f[i];
}

mint choose(int n, int k) {
    if(k > n) return 0;

    return fac(n)/fac(k)/fac(n-k);
}

mint pick(int n, int k) {
    if(k > n) return 0;
    
    return fac(n)/fac(n-k);
}

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> m;

    if(m < n) {
        cout << 0 << '\n';
        return 0;
    }

    bool pos = true;
    mint ans = 0;
    for(int i = 0; i <= n; ++i) {
        mint a = choose(n, i) * pick(m, i);
        mint b = pick(m-i, n-i);
        if(pos) {
            ans += a*b*b;
        } else {
            ans -= a*b*b;
        }
        pos = !pos;
    }

    cout << ans << '\n';
    
    return 0;
}


Measured memory_bytes: 5604