#arc065a. [arc065_a]Daydream
[arc065_a]Daydream
Problem Statement
You are given a string consisting of lowercase English letters. Another string is initially empty. Determine whether it is possible to obtain by performing the following operation an arbitrary number of times:
- Append one of the following at the end of :
dream
,dreamer
,erase
anderaser
.
Constraints
- consists of lowercase English letters.
Input
The input is given from Standard Input in the following format:
Output
If it is possible to obtain , print YES
. Otherwise, print NO
.
Sample Input 1
erasedream
Sample Output 1
YES
Append erase
and dream
at the end of in this order, to obtain .
Sample Input 2
dreameraser
Sample Output 2
YES
Append dream
and eraser
at the end of in this order, to obtain .
Sample Input 3
dreamerer
Sample Output 3
NO