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# 1737. Change Minimum Characters to Satisfy One of Three Conditions

<https://leetcode.com/problems/change-minimum-characters-to-satisfy-one-of-three-conditions>

## Description

You are given two strings `a` and `b` that consist of lowercase letters. In one operation, you can change any character in `a` or `b` to **any lowercase letter**.

Your goal is to satisfy **one** of the following three conditions:

* **Every** letter in `a` is **strictly less** than **every** letter in `b` in the alphabet.
* **Every** letter in `b` is **strictly less** than **every** letter in `a` in the alphabet.
* **Both** `a` and `b` consist of **only one** distinct letter.

Return *the **minimum** number of operations needed to achieve your goal.*

**Example 1:**

```
**Input:** a = "aba", b = "caa"
**Output:** 2
**Explanation:** Consider the best way to make each condition true:
1) Change b to "ccc" in 2 operations, then every letter in a is less than every letter in b.
2) Change a to "bbb" and b to "aaa" in 3 operations, then every letter in b is less than every letter in a.
3) Change a to "aaa" and b to "aaa" in 2 operations, then a and b consist of one distinct letter.
The best way was done in 2 operations (either condition 1 or condition 3).
```

**Example 2:**

```
**Input:** a = "dabadd", b = "cda"
**Output:** 3
**Explanation:** The best way is to make condition 1 true by changing b to "eee".
```

**Constraints:**

* `1 <= a.length, b.length <= 105`
* `a` and `b` consist only of lowercase letters.

## ac

```java
```