import java.io.*; 
public class TestPrime{
   public static void main(String args[]) throws IOException{
      int num;
      boolean prime=true; 
      InputStreamReader in=new InputStreamReader(System.in); 
      BufferedReader bin=new BufferedReader(in);
      System.out.println("һ");
      num=Integer.parseInt(bin.readLine());
      for(int m=2;m<=num/2;m++) { 
         if((num%m)==0) {
            prime=false; 
            break;
         }
      }
      if(prime) 
         System.out.println(num+"");
      else 
         System.out.println(num+"");
   }
}
