import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int x = sc.nextInt();
        boolean end = judge(x);
        while(!end){
            x++;
            end = judge(x);
        }
        System.out.println(x);
    }
    public static boolean judge(int x){
        if(x==2){
            return true;
        }
        if(x%2==0){
            return false;
        }
        for(int i = 3;i*i<=x;i+=2){
            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