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 <stdio.h>
#include <stdlib.h>
#include <string.h>
using namespace std;

int n,i,j,k,Ans;
int pre[100005],ans[100005];
char s[100005];

int main()
{
	scanf("%s",s+1);n=strlen(s+1);
	for(i=1;i<=300;++i)ans[i]=-1;
	for(i=1;i<=n;++i)
	{
		k=i-pre[s[i]];
		if(k>ans[s[i]])ans[s[i]]=k;
		pre[s[i]]=i;
	}
	Ans=10000;
	for(i='a';i<='z';++i)
	{
		k=n+1-pre[i];
		if(k>ans[i])ans[i]=k;
		if(ans[i]<Ans)Ans=ans[i];
	}
	printf("%d\n",Ans-1);
}