#include <iostream>
#include <vector>

long long modpow(int a, long long n, int mod) {
  long long res = 1;
  long long apow = a; // a^1, a^2, a^4, ...
  while (n) {
    if (n & 1LL)
      res = (res * apow) % mod;
    apow = apow * apow % mod;
    n = n >> 1;
  }
  return res;
}

class Combination {
private:
  const int max;
  const int mod;
  std::vector<long long> fac;  // fac[k] = k! in Fp
  std::vector<long long> finv; // finv[k] = (k!)^-1 in Fp
public:
  Combination(int max, int mod)
      : max(max), mod(mod), fac(max, -1), finv(max, -1) {
    std::vector<long long> inv(max, -1); // inv[k] = k^-1 in Fp
    fac[0] = fac[1] = 1;
    inv[1] = 1;
    finv[0] = finv[1] = 1;
    for (int i = 2; i < max; ++i) {
      fac[i] = fac[i - 1] * i % mod;
      inv[i] = mod - inv[mod % i] * (mod / i) % mod;
      finv[i] = finv[i - 1] * inv[i] % mod;
    }
  }
  long long operator()(int n, int k) const {
    if (n < k || n < 0 || k < 0)
      return 0;
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
  }
};

int main() {
  long long N;
  int M;
  std::cin >> N >> M;

  int mod = 1000000007;
  const int MAX = 1000000;
  Combination comb(MAX, mod);

  long long res = 0;
  for (int j = 0; j <= M; ++j) {
    long long tmp = 1;
    tmp = tmp * modpow(j, N, mod) % mod;
    tmp = tmp * comb(M, j) % mod;

    if ((M - j) % 2 == 1)
      tmp = mod - 1 * tmp;
    res = (res + tmp) % mod;
  }
  std::cout << res << std::endl;
}