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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function reverse(s) {
  return s.split('').reverse().join('');
}
 
function r_search(input){
  const words = ['dreamer', 'dream', 'eraser', 'erase'];
  const reversed_words = words.map(x => reverse(x));
  var current_input = reverse(input);

  length_check_loop: while(current_input.length > 0){
    for(word of reversed_words){
      if(current_input.startsWith(word)){
        current_input = current_input.substring(word.length)
        continue length_check_loop;
      }
    }
    return false;
  }
  return true;
}
 
function main(input) {
  if(r_search(input)){
    console.log('YES');
  }else{
    console.log('NO');
  }
}
 
main(require('fs').readFileSync('/dev/stdin', 'utf8'));