import java.util.*;
import java.io.*;
public class Main {
	public static void main(String[] args){
	  Scanner sc = new Scanner(System.in);
      String str = sc.nextLine();
      str = str.replaceAll("eraser", " ");
      str = str.replaceAll("erase", " ");
      str = str.replaceAll("dreamer", " ");
      str = str.replaceAll("dream", " ");
      int strNum = str.split(" ").length;
      if(strNum>0){
        System.out.println("NO");
      } else {
        System.out.println("YES");
      } 
	}
}
/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