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;

typedef long long ll;

const ll MOD = 1000000007;
//const ll INF = 1LL<<60;
int INF = numeric_limits<int>::max();

int main(int, char**) {
	string t; cin >> t;
	int n = t.size();
	int ret = INF;
	for (char c='a'; c<='z'; c++) {
		int ma = 0;
		int cnt = 0;
		for (int i=0; i<n; i++) {
			cnt++;
			if (t[i]==c) {
				ma = max(ma, cnt - 1);
				cnt = 0;
			} else if (i==n-1) {
				ma = max(ma, cnt);
			}
		}
		ret = min(ret, ma);
	}
	cout << ret << endl;
	return 0;
}