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

		int y = 0;
		int r = (int)Math.sqrt(x);

		while ( y == 0 ) {
			int f = 0;
			for ( int i=2; i<=r; i++ ) {
				if ( x%i == 0 ) {
					f = i;
					break;
				}
			}
			if ( f == 0 ) {
				y = x ;
			} else {
				x++;
			}
		}
		System.out.println(y);
	}
}
/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