import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		String s = sc.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 sc = new Scanner(System.in);

		String s = sc.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 sc = new Scanner(System.in);

		String s = sc.next();

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

		Scanner sc = new Scanner(System.in);

		String s = sc.next();

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

		String s = sc.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 sc = new Scanner(System.in);

		String s = sc.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 sc = new Scanner(System.in);

		String s = sc.next();

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