Given an integer array `nums`, return the greatest common divisor of the smallest number and largest number in `nums`.

The greatest common divisor of two numbers is the largest positive integer that evenly divides both numbers.

Example 1:

    Input: nums = [2,5,6,9,10]
    Output: 2
    Explanation:
    The smallest number in nums is 2.
    The largest number in nums is 10.
    The greatest common divisor of 2 and 10 is 2.

Example 2:

    Input: nums = [7,5,6,8,3]
    Output: 1
    Explanation:
    The smallest number in nums is 3.
    The largest number in nums is 8.
    The greatest common divisor of 3 and 8 is 1.

Example 3:

    Input: nums = [3,3]
    Output: 3
    Explanation:
    The smallest number in nums is 3.
    The largest number in nums is 3.
    The greatest common divisor of 3 and 3 is 3.

Constraints:

- `2 <= nums.length <= 1000`
- `1 <= nums[i] <= 1000`