import java.util.Scanner;

class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		int x = sc.nextInt();
		int result;
		if(x == 2) {
			result = x;
		}
		else {
			int count = x;
			while(true) {
				if(isPrime(count)) {
					result = count;
					break;
				}
				count++;
			}
		}
		System.out.println(result);
	}
	public static boolean isPrime(int x) {
		if(x%2==0) {
			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