Problem:
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

Solution in Pascal (FPC 3.0.4) (judge verdict: Wrong Answer)

var

  S : ansistring;
  
begin

  readln(S);
  delete(S, 1, length(S)-7);
  if (pos('dream', S) = length(S)-5+1) or (pos('dreamer', S) = length(S)-7+1) or (pos('erase', S) = length(S)-5+1) or (pos('eraser', S) = length(S)-6+1) then
    writeln('YES')
  else
    writeln('NO');

end.