#include <bits/stdc++.h>
#define fastIO (cin.tie(0), cout.tie(0), ios::sync_with_stdio(false))
#define precise(i) fixed << setprecision(i)
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;

bool isPrime(int num) {
  if (num == 1 || num == 2)
    return true;
  else if (num % 2 == 0)
    return false;
  for (int i = 3; i * i <= num; i += 2) {
    if (num % i == 0)
      return false;
  }
  return true;
}

int main() {
  fastIO;
  int N;
  cin >> N;

  for (int i = N - 100; i < N + 100; ++i) {
    if (!isPrime(i)) {
      cout << i << '\n';
      return 0;
    }
  }

  return 0;
}