First Repeating Character

Given a string s, your task is to find the first character that appears more than once in the string. If no character repeats, output -1.

For example, if the input is "abca", the character 'a' is the first repeating character.

inputFormat

The input contains a single line with the string s. The string may contain letters, digits, or other ASCII characters.

outputFormat

Print a single character, which is the first repeating character in the string. If there is no such character, output -1.

abca

a