import java.util.*;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String text = sc.next();
    text = text.replace("eraser", "-");
    text = text.replace("erase", "-");
    text = text.replace("dreamer", "-");
    text = text.replace("dream", "-");
    text = text.replace("-", "");
    if (text.isEmpty()) {
      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