var output;
var input = require("fs").readFileSync("/dev/stdin", "utf8").trim().split("\n");
var obj = {
  "list" : input,
  "index" : 0,
  "max" : input.length,
  "next" : function(){
    if(!this.hasNext()){throw "NoSuchElementException:次に要素は無いよ";}
    var returnObj = this.list[this.index];
    this.index++;
    return returnObj;
  },
  "hasNext" : function(){return (this.index < this.max);}
}
Main();
function next(){return obj.next();}
function hasNext(){return obj.hasNext();}
function myout(t){console.log(t);}//standard output
function myerr(t){console.error(t);}//standard error
//[no]要素の扱い。数値型
//不明値、異常時:引数そのまま返す
//1:数値へ変換 2:半角SPで分割 4:半角SPで分割し、数値配列へ
//6:1文字に分割 7:1文字に分割し、数値配列へ
//8:半角SPで結合 9:改行で結合 0:文字なしで結合
function myconv(i,no){try{switch(no){case 1:return parseInt(i);case 2:return i.split(" ");case 4:return i.split(" ").map((a)=>Number(a));case 6:return i.split("");case 7:return i.split("").map((a)=>Number(a));case 8:return i.join(" ");case 9:return i.join("\n");case 0:return i.join("");default:return i;}}catch(e){return i;}}
function Main() {
  var s = next();
  while(s.length > 0){
     var five = s.slice(-5);
     var six = s.slice(-6);
     var seven = s.slice(-7);
     if(five == "dream" || five == "erase"){
        s = s.slice(0,s.length - 5);
     }else if(seven == "dreamer"){
        s = s.slice(0,s.length - 7);
	 }else if(six == "eraser"){
		s = s.slice(0,s.length - 6);
	 }else{
        myout("NO");
       return;
     }
  }
  myout("YES");
}
