import java.util.Scanner;
import java.util.Arrays;

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

    s = s.replaceAll("eraser", "-");
    s = s.replaceAll("erase", "-");
    s = s.replaceAll("dreamer", "-");
    s = s.replaceAll("dream", "-");
    s = s.replaceAll("-", "");
    
    if (s.length() == 0) {
      ans = "YES";
    } else {
      ans = "NO";
    }
    System.out.println(ans);
    sc.close();
    return;
  }
}
/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