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;
using ll = long long;
using P = pair<int, int>;
ll INF = 1e10;
int main()
{
    string s;
    cin >> s;
    int n = s.size();

    int ans = n;
    for(int i = 0; i < n; i++)
    {
        char c = s[i];
        int tmp = i;
        int before = i;
        for(int j = i+1; j < n; j++)
        {
            if(s[j] == c)
            {
                int diff = j - before - 1;
                tmp = max(tmp, diff);
                before = j;
            }
            else if(j == n-1)
            {
                int diff = j - before;
                tmp = max(tmp, diff);
            }
        }
        ans = min(ans, tmp);
    }
    cout << ans << endl;
}