# 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.

```python
class Solution:
    def detectCapitalUse(self, word: str) -> bool:
        one_small = False
        one_caps = False
        first_capital = True
        for index, char in enumerate(word):
            if index == 0 and char.isupper():
                first_capital = True
            elif char.isupper() and one_small:
                return False
            elif char.islower() and one_caps:
                return False
            elif char.islower():
                one_small = True
            elif char.isupper():
                one_caps = True
        return True
```