import java.util.Scanner;
public class Num{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		int r;
		int result=0;
		int start = n-100,end = n+100;

		for(int i = start;i<=end;i++){
			for(int j = 2; j<i; j++){
				if(i%j==0){
					result=i;
					break;
				}
			}
			if(result != 0)break;
		}
		

		System.out.println(result);
	}
}