import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
  String s = sc.next();
  s = s.replace("eraser","*");
  s = s.replace("erase","*");
  s = s.replace("dreamer","*");
  s = s.replace("dream","*");
  s = s.replace("*","");
  System.out.println(s.equals("") ? "YES":"NO");
}}
/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