#include <iostream>
#include <fstream>

using namespace std;

int v[10];

int main() {
    fstream f("bac.txt");
    int x, max = 0, nr_ord = 0, c = 0;
    while (f >> x) {
        c++;
        v[x / 10 % 10]++;
        if (v[x / 10 % 10] > max) {
            max++;
            nr_ord = c;
        }
    }
    cout << nr_ord << '\n';
    f.close();
    system("pause");
}