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>
#define x first
#define y second
using namespace std;
typedef long long ll;
const int MAXN = 100500;


bool arr[MAXN];
int n;


int check(string s, char c)
{
	n = s.size();
	bool ok = false;
	for (int i = 0; i < n; i++)
		ok |= arr[i] = s[i] == c;

	if (!ok)
		return MAXN;

	int last_pos = -1;

	int res = -1;

	for (int i = 0; i < n; i++)
	{
		if (arr[i])
		{
			res = max(res, i - last_pos - 1);
			last_pos = i;
		}
	}
	res = max(res, n - last_pos - 1);
	return res;
}

int main()
{                                                     
	ios_base::sync_with_stdio(0);
	

	string s;
	cin >> s;
	int res = MAXN;

	for (char c = 'a'; c <= 'z'; c++)
	{
		res = min(res, check(s, c));
	}

	cout << res << '\n';
	
	return 0;
}