0520. Detect Capital

https://leetcode.com/problems/detect-capital

Description

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.

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