import java.util.Scanner;

/**
 * Created by zzt on 17-1-16.
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();

        s = s.replaceAll("eraser", "");
        s = s.replaceAll("erase", "");
        s = s.replaceAll("dreamer", "");
        s = s.replaceAll("dream", "");

        System.out.println(s.length()>0?"NO":"YES");
    }
}
/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