Given an array arr[] of length N, find the lowest number which has both the maximum and minimum of the array as it's divisor.

Example 1:
Input:
N = 4
arr[] = {3, 4, 8, 6}
Output:
24
Explanation:
Minimum of the array is 3, while the
maximum is 8. The lowest number which has
both 3 and 8 as divisors is 24.
Example 2:
Input:
N = 2
arr[] = {1, 8}
Output:
8
Explanation:
Minimum of the array is 1, while the
maximum is 8. The lowest number which has
both 1 and 8 as divisors is 8.

Your Task:
You don't need to read input or print anything. Your task is to complete the function getNum() which takes an Integer N and an array arr[] of size N as input and returns the integer.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(1)

Constraints:
1 <= N <= 10^{5}
1 <= arr[i] <= 10^{4}

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