import java.util.Scanner;

public class Main {

    private static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        Main instance = new Main();
        instance.solve();
    }

    private void solve() {

        String s = sc.next();

        s = s.replace("eraser","1");
        s = s.replace("erase","1");
        s = s.replace("dreamer","1");
        s = s.replace("dream","1");
        s = s.replace("1","");
        System.out.println(s.equals("") ? "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