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 \leq |S| \leq 2 × 10^5
 - 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.

-----Sample Input-----
eel

-----Sample Output-----
1

We can turn S into a palindrome by the following operation:
 - Swap the 2-nd and 3-rd characters. S is now ele.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

ns = {"__name__": "__main__"}
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = '"""\nどれとペアになるかは最初から確定\n位置を決めれば後は転倒数\n"""\nimport sys\n\ndef bitadd(a,w,bit): #aにwを加える(1-origin)\n \n    x = a\n    while x <= (len(bit)-1):\n        bit[x] += w\n        x += x & (-1 * x)\n \ndef bitsum(a,bit): #ind 1～aまでの和を求める\n \n    ret = 0\n    x = a\n    while x > 0:\n        ret += bit[x]\n        x -= x & (-1 * x)\n    return ret\n\n\nS = input()\n\ndic = {}\n\nfor i,s in enumerate(S):\n\n    if s not in dic:\n\n        dic[s] = []\n\n    dic[s].append(i)\n\npair = [None] * len(S)\nlis = [None] * len(S)\n\nfor i in dic:\n\n    for j in range(len(dic[i]) // 2):\n\n        pair[dic[i][j]] = dic[i][-1-j]\n        pair[dic[i][-1-j]] = -1\n\nnumnone = 0\nfor i in pair:\n    if i == None:\n        numnone += 1\n\nif numnone > 1:\n    print((-1))\n    return\n\nnmax = 0\nfor i,num in enumerate(pair):\n\n    if num == None:\n        lis[i] = len(S)//2\n\n    if num != None and num >= 0:\n        \n        lis[i] = nmax\n        lis[num] = len(S)-1-nmax\n        nmax += 1\n\nBIT = [0] * (len(S)+1)\nans = 0\nlis.reverse()\n\nfor i,num in enumerate(lis):\n\n    num += 1\n    ans += bitsum(num,BIT)\n    bitadd(num,1,BIT)\n\nprint (ans)\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

```

Measured memory_bytes: