#include <bits/stdc++.h>
using namespace std;
const int sz = 5e3 + 10, mod = 1e9 + 7;
int dp[sz][sz];
int po(int x, int y) {
  int re = 1;
  while (y) {
    if (y & 1) re = (1ll * re * x) % mod;
    y >>= 1;
    x = (1ll * x * x) % mod;
  }
  return re;
}
int main() {
  int n, k, an = 0;
  cin >> n >> k;
  dp[0][0] = 1;
  for (int a = 0; a < k; a++) {
    for (int b = 0; b <= min(a, n); b++) {
      dp[a + 1][b] = (dp[a + 1][b] + 1ll * b * dp[a][b]) % mod;
      if (b + 1 <= n)
        dp[a + 1][b + 1] = (dp[a + 1][b + 1] + 1ll * (n - b) * dp[a][b]) % mod;
    }
  }
  for (int a = 0; a <= min(k, n); a++) {
    an = (an + 1ll * dp[k][a] * po(2, n - a)) % mod;
  }
  cout << an;
}
