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)

#[allow(unused_imports)]
use proconio::marker::{Bytes, Chars, Usize1};
use proconio::{fastout, input};
use std::cmp::{max, min};
#[fastout]
fn main() {
    input! {
        s: Chars
    }
    let mut ans = s.len() - 1;
    for i in b'a'..=b'z' {
        let u = check(s.clone(), i as char);
        ans = min(u, ans);
    }
    println!("{}", ans);
}
fn check(s: Vec<char>, c: char) -> usize {
    let mut a = 0;
    let mut pre = 0;
    for i in 0..s.len() {
        if s[i] == c {
            a = max(a, pre);
            pre = 0;
        } else {
            pre += 1;
        }
    }
    a = max(a, pre);
    a
}