#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cstring>
#include <map>
#include <cmath>
#include <set>
#include <vector>

using namespace std;

#define forit(it, s) for(typeof(s.begin()) it = s.begin(); it != s.end(); it++)
#define pb push_back
#define MP make_pair
#define F first
#define S second
#define sz size()
#define LL long long
#define TASK "strings"

const int inf = (1<<30);
const int maxn = int(1e5) + 123;
const int mod = int(1e9) + 7;

string s;
int cnt[30];
int ans = 1, mx;
set < int > q;
vector < int > pos[30];

int main () {
	freopen(TASK".in", "r", stdin);
	freopen(TASK".out", "w", stdout);
		cin >> s;
		for (int i = 0; i < s.sz; i++)
			cnt[s[i] - 'a'] ++;
		for (int i = 0; i < 26; i++)
			mx = max(mx, cnt[i]);
		for (int i = 0; i < s.sz; i++)
			pos[s[i] - 'a'].pb(i);
		for (int i = 0; i < 26; i++)
			if (cnt[i] == mx)
				q.insert(i);
		if (mx == 1) {
			cout << s.sz;
			return 0;
		}
	   	forit(it, q) {
	   		int k = (*it);
	   		char sym = char(k + 'a');
			int len = inf;
			for (int i = 1; i < pos[k].sz; i++) {
				len = min(len, pos[k][i] - pos[k][i - 1]);
			}
			int l;
			for (l = 1; l <= len; l++) {
				set < char > cur;
				for (int i = 0; i < pos[k].sz; i++)
					cur.insert(s[pos[k][i] + l - 1]);
				if (cur.sz != 1) break;
			}
			ans = max(ans, l - 1);
	   	}
	   	cout << ans;
	return 0;
}