#line 1 "main.cpp"
#include <atcoder/all>
#line 2 "library/src/template.hpp"
#include<bits/stdc++.h>
#define rep(i, N) for (int i = 0; i < (N); i++)
#define all(x) (x).begin(),(x).end()
#define popcount(x) __builtin_popcount(x)
using i128=__int128_t;
using ll = long long;
using ld = long double;
using graph = std::vector<std::vector<int>>;
using P = std::pair<int, int>;
constexpr int inf = 1e9;
constexpr ll infl = 1e18;
constexpr ld eps = 1e-6;
const long double pi = acos(-1);
constexpr uint64_t MOD = 1e9 + 7;
constexpr uint64_t MOD2 = 998244353;
constexpr int dx[] = { 1,0,-1,0 };
constexpr int dy[] = { 0,1,0,-1 };
template<class T>constexpr inline void chmax(T&x,T y){if(x<y)x=y;}
template<class T>constexpr inline void chmin(T&x,T y){if(x>y)x=y;}
#line 3 "main.cpp"
using namespace std;
using mint = atcoder::modint1000000007;

template <typename mint,int MAX>
class combination {
    mint factorial[MAX + 1];
    mint factorial_inv[MAX + 1];

public:
    constexpr explicit combination() noexcept {
        factorial[0] = 1;
        for (int i = 1; i <= MAX; ++i) {
            factorial[i] = factorial[i - 1] * i;
        }
        factorial_inv[MAX] = factorial[MAX].inv();
        for (int i = MAX; i > 0; --i) {
            factorial_inv[i - 1] = factorial_inv[i] * i;
        }
    }

    constexpr mint com(int n, int r) const noexcept {
        assert(n >= r);
        return factorial[n] * factorial_inv[r] * factorial_inv[n - r];
    }
};
combination<mint, (int)1e5> com;
int main() {
    ll n, m;
    cin >> n >> m;
    if (n < m) {
        puts("0");
        return 0;
    }
    mint ans = 0;
    mint p = -1;
    for (int c = m; c >= 1; --c) {
        ans += (p *= -1) * com.com(m, c) * (mint(c).pow(n));
    }
    cout << ans.val() << '\n';
}