#include <bits/stdc++.h>
using namespace std;
int f[5010][5010];
int n, k;
const int mod = 1e9 + 7;
int fast_pow(int x, int a) {
  int ans = 1;
  for (; a; a >>= 1, x = 1ll * x * x % mod)
    if (a & 1) ans = 1ll * ans * x % mod;
  return ans;
}
int dp(int a, int b) {
  if (f[a][b] >= 0) return f[a][b];
  int c = n - b;
  if (a == 0) {
    f[a][b] = fast_pow(2, c);
    return f[a][b];
  }
  f[a][b] = ((b ? 1ll * b * dp(a - 1, b) : 0) +
             (c ? 1ll * c * dp(a - 1, b + 1) : 0)) %
            mod;
  return f[a][b];
}
int main() {
  scanf("%d%d", &n, &k);
  memset(f, -1, sizeof(f));
  printf("%d", dp(k, 0));
}
