import java.util.*;

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

        S = S.replaceAll("eraser", "0");
        S = S.replaceAll("erase", "0");
        S = S.replaceAll("dreamer", "0");
        S = S.replaceAll("dream", "0");
        S = S.replaceAll("0", "");

        if (S.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