Extract the Greatest Digit

Given a non-negative integer n, find and print the greatest digit present in it. For example, if n = 52749, then the digits are 5, 2, 7, 4, 9 and the greatest digit is 9. More formally, let the digits of n be represented as \(d_0, d_1, \ldots, d_k\); you need to compute \(\max\{d_0, d_1, \ldots, d_k\}\).

You are required to read the input from stdin and print the result to stdout.

inputFormat

The input consists of a single line containing a non-negative integer n (0 \(\leq n \leq 10^{18}\)).

outputFormat

Output the greatest digit from the given integer n to stdout.

52749

9