#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)

int main(void){
  int n;
  cin >> n;
  for(int i=n-100;i<=n+100;i++)
  {
    for(int j=2;j*j<=i;j++)
    {
      if(i%j==0)
      {
        cout << i << endl;
        return 0;
      }
    }
  }
  return 0;
}