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)

"use strict";
    
const main = arg => {
    arg = arg.trim().split("\n");
    const S = arg[0].split("");
    const reversed = [...S].reverse();
    
    let temp = [];
    
    for(let i in S) {
        if(S.slice(-5).join("") === "erase" || S.slice(-5).join("") === "dream") {
            S.splice(S.length - 5, 5);
        } else if(S.slice(-6).join("") === "eraser" || S.slice(-6).join("") === "dreamer") {
            S.splice(S.length - 6, 6);
        } else {
            console.log("NO");
            return;
        }
    }
    
    console.log("YES");
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));