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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val s = readLine()!!
    var ans = Int.MAX_VALUE
    for (last in 'a'..'z') {
        ans = Math.min(ans, solve(s, last))
    }
    println(ans)
}

fun solve(S: String, last: Char): Int {
    if (!S.contains(last)) {
        return Int.MAX_VALUE
    }
    var res = 0
    var s = S
    while (true) {
        if (s == last.toString().repeat(s.length)) {
            return res
        }
        s = (0 until s.length - 1).map {
            when (last) {
                s[it], s[it + 1] -> last
                else -> s[it]
            }
        }.joinToString("")
        res++
    }
}