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 Ruby (2.3.3) (judge verdict: Runtime Error)

S = gets.strip

if S=='zyxwvutsrqponmlkjihgfedcba'
    puts -1
    exit
end

ans=''
if S.size==26
    j=-1
    (0..S.size-2).reverse_each do |i|
        if S[i]>S[i+1]
            j=i
            break
        end
    end
    key=S[j-2]
    nokori=S[j,99]
    #p ans
    #p key
    #p nokori
    nokoris=nokori.split("").sort.reverse.join
    #p nokoris
    if nokoris==nokori #基を変える
        ans=S[0,j-2]
        nokori.split("").sort.each do |s|
            if s>key
                ans+=s
                break
            end
        end
    else
        ans=S[0,j-1]
        s=S[j]
        (j+2..S.size-1).each do |i|
            s<<S[i]
        end
        s=s.split("").sort
        s.each
        ans+=s[0]
    end
else
    arr=S.split("")
    ('a'..'z').each do |a|
        if !arr.include?(a)
            ans=S+a
            break
        end
    end
end

puts ans