maxlengthuniquesubstr

#include<bits/stdc++.h>
using namespace std;

int main() {

    #ifndef ONLINE_JUDGE
    // for getting input from input.txt
    freopen("input.txt", "r", stdin);
    // for writing output to output.txt
    freopen("output.txt", "w", stdout);
    #endif

    string s;
    cin >> s;

    int vis[256]={-1};
    int n=s.size();

    int start=-1;
    int ms=0;
    for(int i=0;i<n;i++){
        if(vis[s[i]] > start){
           start = vis[s[i]];
        }
            vis[s[i]]=i;
            ms = max(ms,i-start);
    }

    cout << ms << endl;

    return 0;
}