### Problem Statement

You are given a string S consisting of lowercase English letters. Determine whether we can turn S into a palindrome by repeating the operation of swapping two adjacent characters. If it is possible, find the minimum required number of operations.

### Constraints

• 1 ≤ |S| ≤ 2 × 105
• S consists of lowercase English letters.

### Input

Input is given from Standard Input in the following format:

```S
```

### Output

If we cannot turn S into a palindrome, print `-1`. Otherwise, print the minimum required number of operations.

```eel
```

### Sample Output 1

```1
```

We can turn S into a palindrome by the following operation:

• Swap the 2-nd and 3-rd characters. S is now `ele`.

### Sample Input 2

```ataatmma
```

### Sample Output 2

```4
```

We can turn S into a palindrome by the following operation:

• Swap the 5-th and 6-th characters. S is now `ataamtma`.
• Swap the 4-th and 5-th characters. S is now `atamatma`.
• Swap the 3-rd and 4-th characters. S is now `atmaatma`.
• Swap the 2-nd and 3-rd characters. S is now `amtaatma`.

```snuke
```

### Sample Output 3

```-1
```

We cannot turn S into a palindrome.

### Compile Errors

Time Limit: 2 Seconds
Memory Limit: 1024MB
No. of ACs: 2
Your best score: 0
Source: Dunjudge Archive