import java.util.Scanner;
public class Main{
	public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
	String s=sc.next();

	if(s.contains("eraser")) {
		s=s.replace("eraser", "");
	}
	if(s.contains("erase")) {
		s=s.replace("erase", "");
	}
	if(s.contains("dreamer")) {
		s=s.replace("dreamer", "");
	}
	if(s.contains("dream")) {
		s=s.replace("dream", "");
	}
	
	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