#include<iostream>
#include<cassert>
#define rep(i,n) for(i=0;i<(int)(n);i++)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;

int n;

int main(){
    int i,j;
    scanf("%d",&n);
    auto isPrime=[](int x)->bool{
        int i;
        if(x==2)return true;
        if(x<=1||x%2==0)return false;
        for(i=3;i<=x/i;i+=2)if(x%i==0)return false;
        return true;
    };
    for(i=max(3,n-100);i<=n+100;i++){
        if(!isPrime(i)){
            printf("%d\n",i);
            return 0;
        }
    }
    return 0;
}