#include<bits/stdc++.h>
using namespace std;
int main()
{
    string s;
    cin>>s;
    long t=0,e=0,c=0,m=0;
    while(e<s.length())
    {
        char ch=s[e];
        for(long i=t;i<e;i++)
        {
            if(s[i]==ch)
            {
                t=i+1;
                c=e-t;
                break;
            }
        }
        e++;
        c++;
        m=max(m,c);
    }
    cout<<m;
    return 0;
}

//最简单的方法

#include <bits/stdc++.h>
using namespace std;
int l,r,cnt[1001];
string s;
int main()
{
// freopen("filename.in", "r", stdin);
// freopen("filename.out", "w", stdout);
cin>>s;
l=1,r=1;
int ans=0;
for(;r<=s.size();r++)
{
cnt[s[r-1]-'a']++;
while(cnt[s[r-1]-'a']>1)cnt[s[l-1]-'a']--,l++;
ans=max(ans,r-l+1);
}
cout<<ans;
return 0;
}