import java.util.*;
class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    
    String s1 = sc.next();
    String s2 = s1.replace("eraser","").replace("erase","").replace("dreamer","").replace("dream","");
    
    if(s2.length()==0){
      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