Problem Statement  
A simple calculator accepts the following kinds of strings as input:
 
Definition  
 
Constraints  
  input will contain between 3 and 50 characters inclusive.  
  input will have the form <NUM><OP><NUM> where <NUM> is a positive integer between 1 and 10000 inclusive, that may contain leading zeros and <OP> is one of (quotes for clarity) '+','*','', or '/'.  
  input will not contain any spaces.  
Examples  
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