import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String S = sc.next();

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