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