SP10725 STRSEQ - String Subsequence

Given a string of digits, find the smallest nonnegative integer that does not occur in the given string as a subsequence. The length of the string is between 1 and 100000, inclusive.

The input consists of several lines (at most 200), each with a single string S, with between 1 and 10^5 digits.

Print a single line for each string containing the smallest nonnegative integer that does not occur in the given string as a subsequence.