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

		String ans = "NO";
		if(s.matches("(dream|dreamer|erase|eraser)*")) ans = "YES";
		
		System.out.println(ans);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		sc.close();

		String ans = "NO";
		if(s.matches("(dream|dreamer|erase|eraser)*")) ans = "YES";
		
		System.out.println(ans);
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		sc.close();

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

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

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

		String ans = "NO";
		if(s.matches("(dream|dreamer|erase|eraser)*")) ans = "YES";
		
		System.out.println(ans);
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		sc.close();

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