You are working in a ball factory where you have `n` balls numbered from `lowLimit` up to `highLimit` inclusive (i.e., `n == highLimit - lowLimit + 1`), and an infinite number of boxes numbered from `1` to `infinity`.

Your job at this factory is to put each ball in the box with a number equal to the sum of digits of the ball's number. For example, the ball number `321` will be put in the box number `3 + 2 + 1 = 6` and the ball number `10` will be put in the box number `1 + 0 = 1`.

Given two integers `lowLimit` and `highLimit`, return the number of balls in the box with the most balls.

Example 1:

    Input: lowLimit = 1, highLimit = 10
    Output: 2
    Explanation:
    Box Number:  1 2 3 4 5 6 7 8 9 10 11 ...
    Ball Count:  2 1 1 1 1 1 1 1 1 0  0  ...
    Box 1 has the most number of balls with 2 balls.

Example 2:

    Input: lowLimit = 5, highLimit = 15
    Output: 2
    Explanation:
    Box Number:  1 2 3 4 5 6 7 8 9 10 11 ...
    Ball Count:  1 1 1 1 2 2 1 1 1 0  0  ...
    Boxes 5 and 6 have the most number of balls with 2 balls in each.

Example 3:

    Input: lowLimit = 19, highLimit = 28
    Output: 2
    Explanation:
    Box Number:  1 2 3 4 5 6 7 8 9 10 11 12 ...
    Ball Count:  0 1 1 1 1 1 1 1 1 2  0  0  ...
    Box 10 has the most number of balls with 2 balls.

Constraints:

- `1 <= lowLimit <= highLimit <= 105`