import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader buff = null;
		buff = new BufferedReader(new InputStreamReader(System.in));

		String S = buff.readLine();

		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");
	}

	static long f() {
		long ans = 0;

		return ans;
	}
}
/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