#include <bits/stdc++.h>
using namespace std;

signed main(){
  int N; cin >> N;
  for( int i = max( 4, N - 100 ); i <= N + 100; ++i ){
    int ok = 0;
    for( int j = 2; j * j <= i; ++j )
      ok |= i % j == 0;
    if( ok )
      cout << i << endl,
      exit( 0 );
  }
  return 0;
}