Problem Statement  
You will be given a String, eq, representing some simple addition. It will be formatted as a sequence of terms separated by single plus signs. Each term will be either an integer between 0 and 1000, inclusive, or a sequence of lowercase letters, representing a variable. The values of all the variables in eq will be given in a String[], vars, each element of which will be formatted as "VARIABLE VALUE". You should return the sum represented by eq.  
Definition  
 
Constraints  
  eq will be formatted as described in the problem.  
  eq will contain at least one plus sign.  
  eq will contain between 3 and 50 characters, inclusive.  
  Each element of vars will be formatted as "VARIABLE VALUE", where VARIABLE is a sequence of lowercase letters and VALUE is an integer between 0 and 1000, inclusive.  
  None of the integers in the input will have extra leading zeros.  
  Each variable in eq will be present in vars.  
  Each variable in vars will be present in eq, and no variable will occur more than once in vars.  
  Each element of vars will contain at most 50 characters.  
Examples  
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