#include <bits/stdc++.h>

using namespace std;

int main(){
    ifstream input_file("input.txt");
    string text;

    input_file >> text;

    deque<char> frame;

    // Set up
    for(int i = 0; i < 4; ++i){
        frame.push_back(text[i]);
    }

    if(frame[0] != frame[1] && frame[0] != frame[2] && frame[0] != frame[3] &&
       frame[1] != frame[2] && frame[1] != frame[3] && frame[2] != frame[3]){

        cout << "Marker: " << frame[0] << frame[1] << frame[2] << frame[3] << endl;
        return 0;
    }

    for(unsigned int i = 4; i < text.length(); ++i){
        frame.pop_front();
        frame.push_back(text[i]);

        if(frame[0] != frame[1] && frame[0] != frame[2] && frame[0] != frame[3] &&
           frame[1] != frame[2] && frame[1] != frame[3] && frame[2] != frame[3]){

            // cout << "Marker: " << frame[0] << frame[1] << frame[2] << frame[3] << endl;
            cout << i + 1 << endl;
            return 0;
        }
    }

    return 0;
}