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)

// AtCoder Grand Contest 016
// A - Shrinking

#include <bits/stdc++.h>

using namespace std;
typedef long long int ll;


string s;
int ans;

int main() {

    int span, idx, pre_idx;

    cin >> s;

    ans = s.length();
    for (char c = 'a'; c <= 'z'; c++) {
        span = 0;
        pre_idx = -1;
        while ((decltype(string::npos))(idx = s.find_first_of(c, pre_idx + 1)) != string::npos) {
            span = max(span, idx - pre_idx - 1);
            pre_idx = idx;
        }
        span = max(span, (int)s.length() - pre_idx - 1);
        ans = min(ans, span);
    }

    cout << ans << endl;

    return 0;

}