import java.util.Scanner;

public class Main{
	static boolean ip(int x){
		if(x<=3) return true;
		else{
			for(int i=2;i*i<=x;i++){
				if(x%i==0) return false;
			}
			return true;
		}
	}
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
        	int n=sc.nextInt();
        	for(int i=n-100;i<=n+100;i++){
        		if(!ip(i)){
        			System.out.println(i);
        			break;
        		}
        	}
        }
    }
}