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 main()
{
  string s;
  cin >> s;
  set<char> st;
  for (int i = 0; i < s.size(); i++)
  {
    st.insert(s[i]);
  }
  vector<int> ans;
  for (auto itr = st.begin(); itr != st.end(); itr++)
  {
    int tmp = 0, cnt = 0;
    for (int i = 0; i < s.size(); i++)
    {
      if (s[i] == *itr)
      {
        tmp = max(tmp, cnt);
        cnt = 0;
      }
      else
        cnt++;
    }
    tmp = max(tmp, cnt);
    ans.push_back(tmp);
  }
  sort(ans.begin(), ans.end());
  cout << ans[0] << endl;
}