#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main(int argc, char* argv[])
{
    string signal;
    cin >> signal;

    for (int i = 0; i < signal.size()-4; i++)
    {
        string segment = signal.substr(i,4);
        sort(segment.begin(), segment.end());
        if (segment.end() == std::unique(segment.begin(), segment.end()))
        {
            cout << i+4 << endl;
            break;
        }
    }
}