/* template.cpp [[[ */
#include <bits/stdc++.h>
using namespace std;
#define get_macro(a, b, c, d, name, ...) name
#define rep(...) get_macro(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep(...) get_macro(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define rep1(n) rep2(i_, n)
#define rep2(i, n) rep3(i, 0, n)
#define rep3(i, a, b) rep4(i, a, b, 1)
#define rep4(i, a, b, s) for (ll i = (a); i < (ll)(b); i += (ll)s)
#define rrep1(n) rrep2(i_, n)
#define rrep2(i, n) rrep3(i, 0, n)
#define rrep3(i, a, b) rrep4(i, a, b, 1)
#define rrep4(i, a, b, s) for (ll i = (ll)(b) - 1; i >= (ll)(a); i -= (ll)s)
#define each(x, c) for (auto &&x : c)
#define fs first
#define sc second
#define all(c) begin(c), end(c)
using ui = unsigned;
using ll = long long;
using ul = unsigned long long;
using ld = long double;
const int inf = 1e9 + 10;
const ll inf_ll = 1e18 + 10;
const ll mod = 1e9 + 7;
const ll mod9 = 1e9 + 9;
const int dx[]{-1, 0, 1, 0, -1, 1, 1, -1};
const int dy[]{0, -1, 0, 1, -1, -1, 1, 1};
template<class T, class U> void chmin(T &x, const U &y){ x = min<T>(x, y); }
template<class T, class U> void chmax(T &x, const U &y){ x = max<T>(x, y); }
struct prepare_ { prepare_(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(12); } } prepare__;
/* ]]] */

ll modpow(ll x, ll y, ll m = mod){
  ll s = 1;
  while (y){
    if (y & 1) s = s * x % m;
    x = x * x % m;
    y >>= 1;
  }
  return s;
}

ll modinv(ll x, ll m = mod){
  return modpow(x, m - 2, m);
}

ll modcomb(ll x, ll y, ll m = mod){
  if (y < 0 || x < y) return 0;
  ll s = 1;
  rep(i, y){
    s = s * (x - i) % m;
    s = s * modinv(i + 1) % m;
  }
  return s;
}

int main(){
  ll n, m;
  cin >> n >> m;
  if (n < m) cout << "0\n", exit(0);
  ll s = 0, sgn = 1;
  rrep(i, 1, m + 1){
    s = (s + modpow(i, n) * modcomb(m, i) * sgn % mod + mod) % mod;
    sgn *= -1;
  }
  cout << s << endl;
}