e-olymp
Competitions

December 2 - BMTK Programming School, Small League

Maximum digit in a number

Find the maximum digit in a positive integer n.

Input

One positive integer n (n < 1018).

Output

Print the maximum digit in a positive integer n.

Time limit 1 second
Memory limit 128 MiB
Input example #1
2354
Output example #1
5
Input example #2
609432232423423
Output example #2
9