Problem Statement  
You will be given a int[] a and two ints lower and upper. Return the number of integers between lower and upper, inclusive, that are multiples of all members of a.  
Definition  
 
Constraints  
  a will contain between 1 and 50 elements, inclusive.  
  Each element of a will be between 1 and 100, inclusive.  
  upper will be between 1 and 2000000000 (2*10^{9}), inclusive.  
  lower will be between 1 and upper, inclusive.  
Examples  
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