output_description: If it is possible to obtain S = T, print `YES`. Otherwise, print `NO`.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      S
attempt: def dream(s):
    ss=s
    s=s.replace("maerd","")
    s=s.replace("resare","")
    s=s.replace("esare","")
    s=s.replace("remserd","")
   
     if s=="":
      return "YES"
    else:
      return "NO"
  s=input()
  s=s[::-1]
  print(dream(s))
problem_description: 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`.
samples: [{"input": "erasedream", "output": "YES\n    \n\nAppend `erase` and `dream` at the end of T in this order, to obtain S = T.\n\n* * *"}, {"input": "dreameraser", "output": "YES\n    \n\nAppend `dream` and `eraser` at the end of T in this order, to obtain S = T.\n\n* * *"}, {"input": "dreamerer", "output": "NO"}]