#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))

#define MOD 1000000007

int isPrime(int n){
  int i;

  if(n < 2){
    return 1;
  }
  else if(n == 2){
    return 1;
  }

  if(n % 2 == 0){
    return 0;
  }
 
  for(i = 3; i * i <= n; i += 2){
    if(n % i == 0){
      return 0;
    }
  }

  return 1;
}


int main(){
	int n;
	cin>>n;
	rep(i,n-100,n+101){
		if(isPrime(i)==0){
			cout << i << endl;
			return 0;
		}
	}
	return 0;
}