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: Wrong Answer)

fun main(args : Array<String>) {
    val s = readLine()!!
    val lCnt = mutableMapOf<Char, Int>()

    for (i in 1 until s.length) {
        lCnt[s[i]] = (lCnt[s[i]] ?: 0) + 1
    }

    val target = lCnt.maxBy { it.value }?.key
    var ss = s
    var cnt = 0

    while (ss != target.toString().repeat(s.length-cnt)) {
        var tmp = ""
        for (i in 0 until ss.length-1) {
            if (ss[i+1] == target) {
                tmp += ss[i+1]
            } else {
                tmp += ss[i]
            }
        }
        ss = tmp
        cnt++
    }

    println(cnt)
}