import java.util.Scanner;
import java.util.regex.Pattern;

public class Main {
	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		String s=scanner.next();
		Pattern p=Pattern.compile("^(dream|dreamer|erase|eraser)+$");
		if(p.matcher(s).find()) {
			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