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)

///supercalifragilisticexpialidocious.
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cassert>
#include <cstdlib>
#include <cctype>
#include <ctime>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <numeric>
#include <utility>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <queue>
#include <set>
#include <list>
#include <bitset>
#include <complex>
using namespace std;
#define f first
//#define s second
#define PB pop_back 
#define pb push_back
#define mp make_pair
#define int long long
#define y1 y_golabi
#define sz(s) (int)s.size()
#define seper(n) setprecision(n)
#define all(v) v.begin(),v.end()
#define mem(a,b) memset(a,b,sizeof a)
#define IOS ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
typedef long long ll; 
typedef map<int , int> mii;
typedef pair<int , int> pii; 
typedef map<string , int> msi;
typedef pair<int , string> pis; 
typedef pair<int , pair<int , int> > piii;
int mn = 1e10 , cnt;
string s , t , str;
bool is_Same(string s)
{
	for(int i = 0 ; i < sz(s) ; i ++)
		if(s[i] != s[0])
			return false;
	return true;
}
int32_t main()
{
	cin >> str;
	for(char ch = 'a' ; ch <= 'z' ; ch ++)
	{
		t = "" , s = str , cnt = 0;
		while(!is_Same(s))
		{
			t.clear();
			for(int i = 0 ; i < sz(s) - 1 ; i ++)
				if(s[i] == ch or s[i + 1] == ch)
					t += ch;
				else
					t += s[i];
			s = t , cnt ++;
		}
		mn = min(mn , cnt);
	}
	return cout << mn << endl , 0;
}