import java.util.*;

public class Main {
    public static void main(String[] args) {
        try(Scanner sc = new Scanner(System.in);) {
            String src = sc.nextLine();
            String res = src.replaceAll("eraser", "").replaceAll("erase", "").replaceAll("dreamer", "").replaceAll("dream", "");
            System.out.println(res.length() == 0 ? "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