Problem:
Score : 300 points

Problem Statement

Gotou just received a dictionary. However, he doesn't recognize the language used in the dictionary. He did some analysis on the dictionary and realizes that the dictionary contains all possible diverse words in lexicographical order.

A word is called diverse if and only if it is a nonempty string of English lowercase letters and all letters in the word are distinct. For example, atcoder, zscoder and agc are diverse words while gotou and connect aren't diverse words.

Given a diverse word S, determine the next word that appears after S in the dictionary, i.e. the lexicographically smallest diverse word that is lexicographically larger than S, or determine that it doesn't exist.

Let X = x_{1}x_{2}...x_{n} and Y = y_{1}y_{2}...y_{m} be two distinct strings. X is lexicographically larger than Y if and only if Y is a prefix of X or x_{j} > y_{j} where j is the smallest integer such that x_{j} \neq y_{j}.

Constraints

1 \leq |S| \leq 26

S is a diverse word.

Input

Input is given from Standard Input in the following format:

S

Output

Print the next word that appears after S in the dictionary, or -1 if it doesn't exist.

Sample Input 1

atcoder

Sample Output 1

atcoderb

atcoderb is the lexicographically smallest diverse word that is lexicographically larger than atcoder. Note that atcoderb is lexicographically smaller than b.

Sample Input 2

abc

Sample Output 2

abcd

Sample Input 3

zyxwvutsrqponmlkjihgfedcba

Sample Output 3

-1

This is the lexicographically largest diverse word, so the answer is -1.

Sample Input 4

abcdefghijklmnopqrstuvwzyx

Sample Output 4

abcdefghijklmnopqrstuvx

Solution in PyPy3 (2.4.0) (judge verdict: Runtime Error)

from copy import copy, deepcopy
# from functools import reduce
# from heapq import heapify, heappop, heappush
# from itertools import accumulate, permutations, combinations, combinations_with_replacement, groupby, product
# import math
# import numpy as np  # Pythonのみ！
# from operator import xor
# import re
# from scipy.sparse.csgraph import connected_components  # Pythonのみ！
# ↑cf.  https://note.nkmk.me/python-scipy-connected-components/
# from scipy.sparse import csr_matrix
# import statistics # Pythonのみ
# import string
import sys
sys.setrecursionlimit(10 ** 5 + 10)


def input(): return sys.stdin.readline().strip()


def resolve():
    def main():

        def next_permutation(a):
            """Generate the lexicographically next permutation inplace.

            https://en.wikipedia.org/wiki/Permutation#Generation_in_lexicographic_order
            Return false if there is no next permutation.
            """
            # Find the largest index i such that a[i] < a[i + 1]. If no such
            # index exists, the permutation is the last permutation
            for i in reversed(range(len(a) - 1)):
                if a[i] < a[i + 1]:
                    break  # found
            else:  # no break: not found
                return False  # no next permutation

            # Find the largest index j greater than i such that a[i] < a[j]
            j = next(j for j in reversed(range(i + 1, len(a))) if a[i] < a[j])

            # Swap the value of a[i] with that of a[j]
            a[i], a[j] = a[j], a[i]

            # Reverse sequence from a[i + 1] up to and including the final element a[n]
            a[i + 1:] = reversed(a[i + 1:])
            return True

        alpha = list(chr(ord('a')+i) for i in range(26))

        S = input()
        if len(S) < 26:
            for i in range(len(S)):
                alpha.remove(S[i])
            return S+alpha[0]
        else:
            S = list(S)
            P = S.deepcopy()
            next_permutation(P)
            for i in range(26):
                if P[i] != S[i]:
                    return ''.join(P[:i+1])
            return -1
    print(main())

resolve()