import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		if (s.replaceAll("eraser", "X").replaceAll("erase", "X").replaceAll("dreamer", "X").replaceAll("dream", "X")
				.replaceAll("X", "")
				.equals("")) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}
		sc.close();

	}
}
/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