import java.util.Scanner;
import java.util.List;
import java.util.ArrayList;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String s = sc.nextLine();
    String[] keywords = {"dream", "dreamer", "erase", "eraser"};
    List<String> queue = new ArrayList<String>();
    queue.add(s);
    while (queue.size() > 0) {
      s = queue.remove(queue.size() - 1);
      if (s.isEmpty()) {
        System.out.println("YES");
        return;
      }
      for (int i = 0; i < 4; i++) {
        String keyword = keywords[i];
        String ts = s.replaceAll(keyword, "");
        if (s.length() > ts.length()) queue.add(ts);
      }
    }
    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