200650: [AtCoder]ARC065 C - Daydream

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:0 Solved:0

Description

Score : $300$ points

Problem Statement

You are given a string $S$ consisting of lowercase English letters. Another string $T$ is initially empty. Determine whether it is possible to obtain $S = T$ by performing the following operation an arbitrary number of times:

  • Append one of the following at the end of $T$: dream, dreamer, erase and eraser.

Constraints

  • $1≦|S|≦10^5$
  • $S$ consists of lowercase English letters.

Input

The input is given from Standard Input in the following format:

$S$

Output

If it is possible to obtain $S = T$, print YES. Otherwise, print NO.


Sample Input 1

erasedream

Sample Output 1

YES

Append erase and dream at the end of $T$ in this order, to obtain $S = T$.


Sample Input 2

dreameraser

Sample Output 2

YES

Append dream and eraser at the end of $T$ in this order, to obtain $S = T$.


Sample Input 3

dreamerer

Sample Output 3

NO

Input

题意翻译

# 题目大意 输入一个以英文小写字母组成的字符串S,规定一个空的字符串T,现在你可对字符串T进行你喜欢的操作,问是否能让字符串T变为字符串S? **喜欢的操作如下 :** 在字符串T的末尾加入 “dream”或“dreamer”或“erase”或“eraser”。 ------------ ## 输入格式 一个字符串S ## 输出格式 若可以输出**YES**,否则输出**NO**。

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