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)

// ABC 049

// inputに入力データ全体が入る
function Main(input) {
  var str = input;
  // 正規表現による指定
  str = str.replace(/erase/g, '');
  str = str.replace(/eraser/g, '');
  str = str.replace(/dreamer/g, '');
  str = str.replace(/dream/g, '');

  if(str == "") {
    console.log("YES");
  } else {
    console.log("NO");
  }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));