#### QUESTION:

You are given a string s consisting only of letters ‘a’ and ‘b’. In a single step you can remove one palindromic subsequence from s.

Return the minimum number of steps to make the given string empty.

A string is a subsequence of a given string if it is generated by deleting some characters of a given string without changing its order. Note that a subsequence does not necessarily need to be contiguous.

A string is called palindrome if is one that reads the same backward as well as forward.

**Example 1:**

```
Input: s = "ababa"
Output: 1
Explanation: s is already a palindrome, so its entirety can be removed in a single step.
```

**Example 2:**

```
Input: s = "abb"
Output: 2
Explanation: "abb" -> "bb" -> "".
Remove palindromic subsequence "a" then "bb".
```

**Example 3:**

```
Input: s = "baabb"
Output: 2
Explanation: "baabb" -> "b" -> "".
Remove palindromic subsequence "baab" then "b".
```

**Constraints:**

```
1 <= s.length <= 1000
s[i] is either 'a' or 'b'.
```

#### EXPLANATION:

因为只有a和b, 所以如果一开始不是回环的话, 那么我们可以先去除a, 然后再去除b. 那么最多也就是2步而已.

#### SOLUTION:

```
class Solution {
func removePalindromeSub(_ s: String) -> Int {
return s == String(s.reversed()) ? 1 : 2
}
}
```