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 12.16.1) (judge verdict: Time Limit Exceeded)

function main(input) {
  const args = input.split('').reverse().join('');
  
  while(true){var rplc1 = /maerd/g;
  var rplc2 = /remaerd/g;
  var rplc3 = /esare/g;
  var rplc4 = /resare/g;
  var i = args.replace(rplc1,'');
  var j = i.replace(rplc2,'');
  var k = j.replace(rplc3,'');
  var l = k.replace(rplc4,'');
  var m = l === '';
  if(m){break;}
  }
  
  if(!m){
    console.log('NO');
  }else if(m){
    console.log('YES');
  }
  
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));