{"raw_statement":[{"iden":"problem statement","content":"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.\nA 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.\nGiven 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.\nLet $X = x_{1}x_{2}...x_{n}$ 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 $x_{j} \\neq y_{j}$."},{"iden":"constraints","content":"*   $1 \\leq |S| \\leq 26$\n*   $S$ is a diverse word."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$S$"},{"iden":"sample input 1","content":"atcoder"},{"iden":"sample output 1","content":"atcoderb\n\n`atcoderb` is the lexicographically smallest diverse word that is lexicographically larger than `atcoder`. Note that `atcoderb` is lexicographically smaller than `b`."},{"iden":"sample input 2","content":"abc"},{"iden":"sample output 2","content":"abcd"},{"iden":"sample input 3","content":"zyxwvutsrqponmlkjihgfedcba"},{"iden":"sample output 3","content":"\\-1\n\nThis is the lexicographically largest diverse word, so the answer is `-1`."},{"iden":"sample input 4","content":"abcdefghijklmnopqrstuvwzyx"},{"iden":"sample output 4","content":"abcdefghijklmnopqrstuvx"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}