Problem Statement

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 $S$.

Constraints

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

Input

Input is given from Standard Input in the following format:

$S$

Output

Print the only digit missing in $S$.

Sample Input 1

023456789

Sample Output 1

1

The string 023456789 only lacks $1$. Thus, $1$ should be printed.

Sample Input 2

459230781

Sample Output 2

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.