import java.math.*;
import java.util.*;
import java.io.*;
import java.lang.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner (System.in);
		int x = sc.nextInt();
		if (isPrime(x)) {
			System.out.println(x);
		} else  {
				while (!isPrime(x)) {
					x++;
				}
				System.out.println(x);
			}
		}

		public static boolean isPrime (int a) {
			BigInteger bi = BigInteger.valueOf(a);
			return bi.isProbablePrime(1);
		}
}

/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