import java.util.*;
class Main{
	static Scanner s = new Scanner(System.in);
	public static void main(String[] args) {
		StringBuilder str = new StringBuilder(s.next()
				.replaceAll("eraser", "")
				.replaceAll("dream", "D")
				.replaceAll("er", "R")
				.replaceAll("as", "A"));
		String[] m = {"RAe","DR","D"};
		String b,st;
		boolean f;
		do {
			f=false;
			for(int i=0;i<m.length;i++) {
				b=m[i];
				st = str.toString();
				if(st.endsWith(b)) {
					str.delete(str.length()-b.length(),str.length());
					f=true;
					break;
				}
			}
		}while(f);
		System.out.println((str.toString().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