import java.util.Scanner;

public class N192 {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);
		int N = sca.nextInt();
		int A = N - 100;
		int B = N + 100;

		for (int i = A; i < B; i++) {
			for (int k = 2; k < i; k++) {
				if (i % k == 0) {
					System.out.println(i);
					return;
				}

			}

		}
	}
}