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

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;

#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define loop(i,a,b) for(ull i=(a);i<ull(b);++i)
#define rep(i,n) loop(i,0,n)
#define iter(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define riter(i,c) for(auto i=(c).rbegin(); i!=(c).rend(); ++i)

const double eps = 1e-10;
const double pi  = acos(-1.0);
const double inf = (int)1e8;

#define clr(a,i) memset((a), (i) ,sizeof(a))

bool isPrime(long long x) {
	long long i;
	if ( x < 2 ) return 0;
	else if ( x == 2 ) return 1; /* 2 は素数*/
	if ( x % 2 == 0 ) return 0; /* 偶数は素数ではない*/
	for ( i = 3; i*i <= x; i+=2 ) { /* i が x の平方根以下の間*/
		if ( x % i == 0 ) return 0;
	}
	return 1;
}

int main(){
  int n,a;cin>>n;
  if(n-100>4) a=n-100;else a=4;
  loop(i,a,n+101){
    if(!isPrime(i)){
      cout << i << endl;
      break;
    }
  }
}