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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include	<bits/stdc++.h>
using	namespace	std;

// int/long:		-2147483648 - 2147483648 (-2^31 <= int < 2^31)
// long/long long:	-9223372036854775808 - 9223372036854775807 (-2^63 <= long < 2^63)

#define	INF (1<<29)
//536870912

// lower_bound(A.begin(), A.end(), N)
// upper_bound(...

// bit: &/and, |/or, ^/xor, ~/not

#define	MOD 1000000007

int	main() {
	string s;
	cin >>s;
	vector<vector<int>> A(26, vector<int> {0});
	for (int i=0; i<s.size(); i++)
		A.at(s.at(i)-'a').push_back(i+1);
	for (int i=0; i<26; i++)
		A.at(i).push_back(s.size()+1);
	int S=100;
	for (int i=0; i<26; i++){
		int SS=0;
		for (int j=0; j<A.at(i).size()-1; j++) 
			SS=max(SS, A.at(i).at(j+1)-A.at(i).at(j)-1);
		S=min(S, SS);
	}
	cout << S << endl;
	return 0;
}