#include <bits/stdc++.h>
using namespace std;
int n, k;
long long ans, s2[5001][5001], jc = 1;
long long ksm(int b) {
  long long an = 1, a = 2;
  while (b) {
    if (b & 1) an = (an * a) % (1000000007);
    a = (a * a) % (1000000007);
    b >>= 1;
  }
  return an % (1000000007);
}
int main() {
  scanf("%d%d", &n, &k);
  s2[0][0] = 1;
  for (int i = 1; i <= k; i++) {
    for (int j = 1; j <= i; j++) {
      s2[i][j] =
          (s2[i - 1][j - 1] + (j * s2[i - 1][j]) % (1000000007)) % (1000000007);
    }
  }
  long long kk = ksm(n), nw = ksm((1000000007) - 2);
  for (int i = 0; i <= k; i++) {
    ans = (ans + ((((s2[k][i] * kk)) % (1000000007)) * jc) % (1000000007)) %
          (1000000007);
    kk = (kk * nw) % (1000000007);
    jc = (jc * (n - i)) % (1000000007);
  }
  printf("%lld\n", ans);
  return 0;
}
