import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}

} Main public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	} main {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String s = scanner.next(); s scanner.next() scanner.next scanner if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		} s.matches("(dream|dreamer|erase|eraser)*") s.matches s "(dream|dreamer|erase|eraser)*" {
			System.out.println("YES");
		} System.out.println("YES") System.out.println System.out System System.out "YES" {
			System.out.println("NO");
		} System.out.println("NO") System.out.println System.out System System.out "NO" String[] args args public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}

} public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.next();

		if(s.matches("(dream|dreamer|erase|eraser)*")){
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}
	}

}
