#include <bits/stdc++.h>
       
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
       
class ModInt {
  static int MOD;
  long long x;

 public:
  static void mod(int m) { MOD = m; }

  ModInt(long long v = 0) : x(v % MOD) {
    if (x < 0) x += MOD;
  }

  ModInt& operator+=(const ModInt& r) {
    x += r.x;
    if (x >= MOD) x -= MOD;
    return *this;
  }

  ModInt& operator-=(const ModInt& r) {
    x -= r.x;
    if (x < 0) x += MOD;
    return *this;
  }
  ModInt& operator*=(const ModInt& r) {
    x = (x * r.x) % MOD;
    return *this;
  }
  ModInt& operator/=(const ModInt& r) {
    *this *= r.inverse();
    return *this;
  }

  ModInt operator-() const { return ModInt(-x); }

  ModInt operator+(const ModInt& r) const { return ModInt(*this) += r; }
  ModInt operator-(const ModInt& r) const { return ModInt(*this) -= r; }
  ModInt operator*(const ModInt& r) const { return ModInt(*this) *= r; }
  ModInt operator/(const ModInt& r) const { return ModInt(*this) /= r; }
  bool operator==(const ModInt& r) const { return x == r.x; }
  bool operator!=(const ModInt& r) const { return x != r.x; }

  ModInt inverse() const {
    long long a = x, b = MOD, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }

  ModInt pow(long long n) const {
    ModInt ret(1), mul(x);
    while (n > 0) {
      if (n & 1) ret *= mul;
      mul *= mul;
      n >>= 1;
    }
    return ret;
  }

  friend ostream& operator<<(ostream& os, const ModInt& x) { return os << x.x; }

  friend istream& operator>>(istream& is, ModInt& x) { return is >> x.x; }

  int getMod() { return MOD; }

  long long val() { return x; }
};
int ModInt::MOD = 1000000007;
       
template <typename T>
class Combination {
  vector<T> fact, ifact;

 public:
  Combination(int nMax) : fact(nMax + 1), ifact(nMax + 1) {
    fact[0] = 1;
    for (int i = 0; i < nMax; ++i) fact[i + 1] = fact[i] * (i + 1);
    for (int i = 0; i < nMax + 1; ++i) ifact[i] = fact[i].inverse();
  }

  T factorial(int n) const { return fact[n]; }
  T inverseFactorial(int n) const { return ifact[n]; }

  T P(int n, int k) const {
    if (n < 0 || k < 0 || n < k) return 0;
    return factorial(n) * inverseFactorial(n - k);
  }

  T C(int n, int k) const {
    if (n < 0 || k < 0 || n < k) return 0;
    return factorial(n) * inverseFactorial(n - k) * inverseFactorial(k);
  }

  T H(int n, int k) const {
    if (n < 0 || k < 0) return 0;
    return k == 0 ? 1 : C(n + k - 1, k);
  }
};
class StirlingNumber {
  vector<vector<ModInt>> res;

 public:
  static ModInt calculate(long long N, int K) {
    Combination<ModInt> comb(K);

    ModInt res = 0;
    for (int i = 0; i <= K; ++i) {
      ModInt v = comb.C(K, i) * ModInt(i).pow(N);
      if ((K - i) % 2)
        res -= v;
      else
        res += v;
    }
    res *= comb.inverseFactorial(K);
    return res;
  }
  StirlingNumber(int N, int K) : res(N + 1, vector<ModInt>(K + 1, 0)) {
    res[0][0] = 1;
    for (int n = 1; n <= N; ++n) {
      for (int k = 1; k <= min(n, K); ++k) {
        res[n][k] = res[n - 1][k - 1] + res[n - 1][k] * k;
      }
    }
  }

  const vector<ModInt>& operator[](int n) const { return res[n]; }
};

int main() {
  ll N;
  int M;
  cin >> N >> M;
  Combination<ModInt> comb(M);
  cout << comb.factorial(M) * StirlingNumber::calculate(N, M) << endl;
  return 0;
}