Warehouse Manifest Rarest Digit

A regional warehouse stamps every incoming shipment with a numeric manifest code. An auditor wants to flag, for each manifest, the single digit (0 through 9) that shows up the least often within that code, since rare digits are used to spot-check for transcription errors. You are given one manifest code and must report its rarest digit.

Only digits that actually appear in the code are considered candidates (a digit that never appears is not a candidate). If two or more digits tie for the fewest occurrences, report the smallest of those tied digits.

Input format

A single line containing the manifest code as a string of decimal digits, with no sign and no leading zero unless the code is exactly the single digit 0.

Output format

Print a single character: the rarest digit in the code, as described above.

Constraints

• The code has between 1 and 18 digits.
• Every character of the code is one of 0123456789.
• The code has no leading zero unless it is the single character 0.

1223334

1

77788899

9