Problem

Given a string s, write a function to count the number of unique characters in it. The function should ignore spaces and consider uppercase and lowercase letters as the same character.

Examples

Example 1:

Input: s = 'Hello World'
Output: 10

Explanation: The unique characters are 'H', 'e', 'l', 'o', ' ', 'W', 'r', 'd'. Count = 10.

Example 2:

Input: s = 'Programming'
Output: 8

Explanation: The unique characters are 'P', 'r', 'o', 'g', 'a', 'm', 'i', 'n'. Count = 8.

Constraints

• 1 <= s.length <= 100
• s consists of printable ASCII characters.