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 Go (1.6) (judge verdict: Accepted)

// AGC016A - Shrinking
package main

import "fmt"

func loweralpha() string {
	p := make([]byte, 26)
	for i := range p {
		p[i] = 'a' + byte(i)
	}
	return string(p)
}

func maxInt(a, b int) int {
	if a < b {
		return b
	}
	return a
}
func minInt(a, b int) int {
	if a > b {
		return b
	}
	return a
}
func main() {
	var s string
	fmt.Scan(&s)
	runeS := []rune(s)
	alphabet := []rune(loweralpha())
	ans := 100
	for _, chara := range alphabet {
		temp := 0
		leftMax := 0
		var ri int
		for i, c := range runeS {
			if c == chara {
				leftMax = maxInt(leftMax, temp)
				ri = i
				temp = 0
			} else {
				temp++
			}
		}
		rightMax := len(s) - ri - 1
		ans = minInt(maxInt(rightMax, leftMax), ans)
	}
	fmt.Println(ans)
}