520 - Detect Capital\.

Easy

We define the usage of capitals in a word to be right when one of the following cases holds:

• All letters in this word are capitals, like "USA".

• All letters in this word are not capitals, like "leetcode".

• Only the first letter in this word is capital, like "Google".

Given a string word, return true if the usage of capitals in it is right.

Example 1:

Input: word = "USA"

Output: true

Example 2:

Input: word = "FlaG"

Output: false

Constraints:

• 1 <= word.length <= 100

• word consists of lowercase and uppercase English letters.