import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		String s;
		try (Scanner scanner = new Scanner(System.in)) {
			s = scanner.next();
		}

		boolean canObtain = s.replace("eraser",  " ")
				.replace("erase",   " ")
				.replace("dreamer", " ")
				.replace("dream",   " ")
				.trim()
				.isEmpty();

		if (canObtain) {
			System.out.println("YES");
		} else {
			System.out.println("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