import java.util.*;
import java.lang.*;
public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int X = sc.nextInt();
		loop:for( int i=X; i<=X*2; i++ ){
          if( i==2 ){
					System.out.println(i);
 					break loop;                 
                } 
			for( int j=2; j*j<=i; j++ ){                
				if( i%j==0 ){
					break;
				}
				if( (j+1)*(j+1)>i ){
					System.out.println(i);
					break loop;
				}
			}
		}
	}
}

/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