import java.util.*;


public class Main {
    public static void main(String[] args) {
        // 自分の得意な言語で
        // Let's チャレンジ！！

        Scanner sc = new Scanner(System.in);
        String answer = sc.next();
        if (answer.matches("((dream)|(dreamer)|(erase)|(eraser))*")) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        // 自分の得意な言語で
        // Let's チャレンジ！！

        Scanner sc = new Scanner(System.in);
        String answer = sc.next();
        if (answer.matches("((dream)|(dreamer)|(erase)|(eraser))*")) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} Main public static void main(String[] args) {
        // 自分の得意な言語で
        // Let's チャレンジ！！

        Scanner sc = new Scanner(System.in);
        String answer = sc.next();
        if (answer.matches("((dream)|(dreamer)|(erase)|(eraser))*")) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    } main {
        // 自分の得意な言語で
        // Let's チャレンジ！！

        Scanner sc = new Scanner(System.in);
        String answer = sc.next();
        if (answer.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 answer = sc.next(); answer sc.next() sc.next sc if (answer.matches("((dream)|(dreamer)|(erase)|(eraser))*")) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        } answer.matches("((dream)|(dreamer)|(erase)|(eraser))*") answer.matches answer "((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) {
        // 自分の得意な言語で
        // Let's チャレンジ！！

        Scanner sc = new Scanner(System.in);
        String answer = sc.next();
        if (answer.matches("((dream)|(dreamer)|(erase)|(eraser))*")) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} public class Main {
    public static void main(String[] args) {
        // 自分の得意な言語で
        // Let's チャレンジ！！

        Scanner sc = new Scanner(System.in);
        String answer = sc.next();
        if (answer.matches("((dream)|(dreamer)|(erase)|(eraser))*")) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} Main
import java.util.*;


public class Main {
    public static void main(String[] args) {
        // 自分の得意な言語で
        // Let's チャレンジ！！

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