import java.util.*;

class Main {
	Scanner sc;
	
	private void calc() {
		sc = new Scanner(System.in);
		int X = sc.nextInt();
		
	lp:
		while (true) {
			int n = (int)Math.sqrt(X);
			for (int i = 2; i <= n; i++) {
				if (X%i == 0) {
					X++;
					continue lp;
				}
			}
			System.out.println(X);
			break;
		}
	}

	public static void main(String[] args) {
		new Main().calc();
	}
}
/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