import java.util.*;

public class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		
		int X = sc.nextInt();
		boolean flag = true;
		while(flag){
			flag = false;
			for(int i = 2; i < X; i++){
				if(X % i == 0){
					flag = true;
					break;
				}
			}
			if(flag)X++;
		}
		System.out.println(X);
	}
}
/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