import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc=new Scanner(System.in);
		
		int x=sc.nextInt();
		while (!Prime(x)) {
			x++;
		}
		System.out.println(x);
		sc.close();
	}
 
	//素数判定
	public static boolean Prime(int x) {
		if(x==1){
			return false;
		}
		for(int i= 2;i*i<=x;i++) {
			if (x%i==0) {
				return false;
			}
		}
		return true;
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz