Contest: Task: Related: TaskB

Score : $100$ points

You are given a string $S$ of length exactly $9$ consisting of digits.
One but all digits from `0`

to `9`

appear exactly once in $S$.

Print the only digit missing in $S$.

- $S$ is a string of length $9$ consisting of digits.
- All characters in $S$ are distinct.

Input is given from Standard Input in the following format:

$S$

Print the only digit missing in $S$.

023456789

1

The string `023456789`

only lacks $1$.
Thus, $1$ should be printed.

459230781

6

The string `459230781`

only lacks $6$.
Thus, $6$ should be printed.

Note that the digits in the string may not appear in increasing order.