Given a string `s` of zeros and ones, return the maximum score after splitting the string into two non-empty substrings (i.e. left substring and right substring).

The score after splitting a string is the number of zeros in the left substring plus the number of ones in the right substring.

Example 1:

    Input: s = "011101"
    Output: 5
    Explanation:
    All possible ways of splitting s into two non-empty substrings are:
    left = "0" and right = "11101", score = 1 + 4 = 5
    left = "01" and right = "1101", score = 1 + 3 = 4
    left = "011" and right = "101", score = 1 + 2 = 3
    left = "0111" and right = "01", score = 1 + 1 = 2
    left = "01110" and right = "1", score = 2 + 1 = 3

Example 2:

    Input: s = "00111"
    Output: 5
    Explanation: When left = "00" and right = "111", we get the maximum score = 2 + 3 = 5

Example 3:

    Input: s = "1111"
    Output: 3

Constraints:

- `2 <= s.length <= 500`
- The string `s` consists of characters `'0'` and `'1'` only.