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 C++ (GCC 9.2.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using intl = long long;
using itnl = long long;//typo用
using uintl = unsigned long long;
using itn = int;//typo用
using ld = long double;
using namespace std;
#define rep(i, n) for(intl i = 0; i < (intl)(n); i++)
#define rrep(i, n) for(intl i = (intl)(n) - 1; i >= 0; i--)
#define repi(i, a, b) for(intl i = (intl)(a); i < (intl)(b); i++)
#define rrepi(i, a, b) for(intl i = (intl)(a) - 1; i >= (intl)(b); i--)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define m0(x) memset(x,0,sizeof(x))
#define m1(x) memset(x,1,sizeof(x))
#define fill(x,y) memset(x,y,sizeof(x))
#define alength(a) (sizeof(a) / sizeof(a[0]))
#define debug(x) cout << #x << ":" << x << endl
#define rdebug(i,x) rep(i, alength(x))cout << #x << "[" << i << "]:" << x[i] << endl//1次元配列の出力
#define rrdebug(i, j, x) rep(i, alength(x))rep(j, alength(x[i]))cout << #x << "[" << i << "][" << j << "]:" << x[i][j] << endl//二次元配列の出力
#define pb push_back
#define mp make_pair
#define pii pair<intl,intl>
const intl INF = 1e9;
const intl MOD = 1e9+7;
const ld EPS = 1.0e-14;//-9
const ld PI = acos(-1);
void fp(bool f){cout << (f ? "Yes" : "No") << endl;}
void fp(bool f, string s, string t){cout << (f ? s : t) << endl;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) {a = b; return true;} return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) {a = b; return true;} return false; }
intl gcd(intl a, intl b){ if(!b)return a; return gcd(b, a % b); }
intl lcm(intl a,intl b){ return a / gcd(a, b) * b; }
intl kai(intl k){//k!を求める関数,
    intl a = 1;
    for(int i = 2; i <= k; i++){
        a *= i;
    }
    return a;
}
intl digit10(intl a){//aを10進数で表したときの桁数を求める関数
    intl b = 0;
    do{
        a /= 10;
        b++;
    }while(a);
    return b;
}


signed main(){
    cout << fixed << setprecision(10);
    string s;
    cin >> s;
    intl len = s.length();
    if(len < 26){
        bool f[26];
        m0(f);
        rep(i,len)f[s[i] - 'a'] = true;
        rep(i,26){
            if(!f[i]){
                s += (char)(i + 'a');
                break;
            }
        }
    }
    else{
        vector<char> v;
        rep(i,len)v.pb(s[i]);
        next_permutation(all(v));
        string t = "";
        rep(i,26){
            t += v[i];
            if(s[i] != v[i])break;
        }
        s = t;
        if(s == "a")s = "-1";
    }
    cout << s << endl;
    return 0;
}