import java.util.Scanner;

public class Main {
    public static void main(String args[]) throws Exception {
        Scanner s = new Scanner(System.in);
        String n = s.next();
        n = n.replaceAll("eraser", "");
        n = n.replaceAll("erase", "");
        n = n.replaceAll("dreamer", "");
        n = n.replaceAll("dream", "");
        
        System.out.println(n.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