Problem:
Score : 300 points

Problem Statement

Snuke can change a string t of length N into a string t' of length N - 1 under the following rule:

For each i (1 ≤ i ≤ N - 1), the i-th character of t' must be either the i-th or (i + 1)-th character of t.

There is a string s consisting of lowercase English letters.
Snuke's objective is to apply the above operation to s repeatedly so that all the characters in s are the same.
Find the minimum necessary number of operations.

Constraints

1 ≤ |s| ≤ 100

s consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

s

Output

Print the minimum necessary number of operations to achieve the objective.

Sample Input 1

serval

Sample Output 1

3

One solution is: serval → srvvl → svvv → vvv.

Sample Input 2

jackal

Sample Output 2

2

One solution is: jackal → aacaa → aaaa.

Sample Input 3

zzz

Sample Output 3

0

All the characters in s are the same from the beginning.

Sample Input 4

whbrjpjyhsrywlqjxdbrbaomnw

Sample Output 4

8

In 8 operations, he can change s to rrrrrrrrrrrrrrrrrr.

Solution in Rust (1.42.0) (judge verdict: Accepted)

use proconio::input;
use proconio::marker::Chars;

fn main() {
    input! {
        s: Chars,
    };
    let mut ans = 100;
    for i in 0..26 {
        let c = (i as u8 + 'a' as u8) as char;
        let (l, r) = {
            let mut max_l = 0;
            let mut l = 0;
            for &s_i in s.iter() {
                if s_i == c {
                    max_l = std::cmp::max(max_l, l);
                    l = 0;
                } else {
                    l += 1;
                }
            }
            (max_l, l)
        };
        let v = r + std::cmp::max(0, l - r);
        ans = std::cmp::min(ans, v);
    }
    println!("{}", ans);
}