import java.util.Scanner;

public class No0192 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int min = N - 100;
		int max = N + 100;
		int ans = 0;
		
		if(isComposite(N)){
			ans = N;
		}
		else{
			for(int i = min; i < (max + 1); i++){
				if(isComposite(i)) {
					ans = i;
					break;
				}
			}
		}
		System.out.println(ans);
	}
	
	static boolean isComposite(int num){
		
		if(num < 3) return false;
		for(int i = 2; i < num; i++){
			if(num % i == 0) return true;
		}
		return false;
	}
}