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.
|-||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*109), inclusive.|
|-||lower will be between 1 and upper, inclusive.|