import java.util.*;
public class Test {
  public static void main(String args[]){
    Random r = new Random();
    for(int i=0;i<4;i++){
     switch(r.nextInt(3))
     {
         case 0:
             System.out.println(Character.toChars(r.nextInt(10)+48));
            break;
        case 1:
            System.out.println(Character.toChars(r.nextInt(26)+65));
            break;
        case 2:
            System.out.println(Character.toChars(r.nextInt(26)+97));
            break;
     }
    }
  }
}