#include <iostream>
#include <iomanip>

#include <algorithm>
#include <math.h>

#include <string>
#include <list>
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed;//
    //cout << setprecision(6);//

	int N;
	cin>>N;//[101,1000]
	for(int i=N-100;i<=(N+100);++i){
		for(int k= 2;k<sqrt(i*1.0)+1;++k){
			if(i%k == 0 && i != k){
				P(i);
				return 0;
			}
		}
	}

    return 0;
}