using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using static System.Console;
using static System.Math;
using static ConsoleApplication.Utils;

namespace ConsoleApplication
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var s = ReadLine();
            var dp = new bool[1000000];
            dp[0] = true;
            for (var i = 0; i < s.Length; ++i)
            {
                if (!dp[i]) continue;
                if (i + 5 <= s.Length && s.Substring(i, 5) == "dream") dp[i+5] = true;
                if (i + 7 <= s.Length && s.Substring(i, 7) == "dreamer") dp[i+7] = true;
                if (i + 5 <= s.Length && s.Substring(i, 5) == "erase") dp[i+5] = true;
                if (i + 6 <= s.Length && s.Substring(i, 6) == "eraser") dp[i+6] = true; 
            }
            var res = dp[s.Length] ? "YES" : "NO";
            WriteLine(res);
        }
    }

    public static class Utils
    {
        #region Extensions for IO

        public static int ReadInt()
            => ReadLine().ToInt();

        public static IEnumerable<int> ReadInts()
            => ReadStrings().Select(int.Parse);

        public static IEnumerable<int> ReadInts(int count)
            => ReadLines(count).Select(int.Parse);

        public static long ReadLong()
            => ReadLine().ToLong();

        public static IEnumerable<long> ReadLongs()
            => ReadStrings().Select(long.Parse);

        public static ulong ReadUlong()
            => ReadLine().ToUlong();

        public static IEnumerable<ulong> ReadUlongs()
            => ReadStrings().Select(ulong.Parse);


        public static IEnumerable<string> ReadStrings()
            => ReadLine().Split(' ');

        public static IEnumerable<string> ReadLines(int n)
        {
            foreach (var i in Enumerable.Range(0, n))
            {
                yield return ReadLine();
            }
        }

        #endregion

        #region Extensions of int

        public static bool IsOdd(this int n)
            => !n.IsEven();

        public static bool IsEven(this int n)
            => n % 2 == 0;

        public static bool CanDivideWith(this int n, int divisor)
            => n % divisor == 0;

        #endregion

        #region Extensions of string

        public static int ToInt(this string str)
            => int.Parse(str);

        public static long ToLong(this string str)
            => long.Parse(str);

        public static ulong ToUlong(this string str)
            => ulong.Parse(str);

        public static double ToDouble(this string str)
            => double.Parse(str);

        public static bool IsNullOrEmpty(this string str)
            => string.IsNullOrEmpty(str);

        #endregion

        public static TSource Min<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
            where TKey : IComparable
            => source.OrderBy(keySelector).First();

        public static TSource Max<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
            where TKey : IComparable
            => source.OrderByDescending(keySelector).First();

        public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
        {
            foreach (var item in source)
            {
                action(item);
            }
        }

        public static IEnumerable<T> Peek<T>(this IEnumerable<T> source, Action<T> action)
        {
            foreach (var item in source)
            {
                action(item);
            }
            return source;
        }
    }
}


Measured memory_bytes: 8024