9
[1, Kocourek Petr, 4, 3, true, nil]
[2, Kocourková Lucie, 4, 3, false, nil]
[3, Kocourek Michal, 5, 6, true, 4]
[4, Kocourková Ivana, 8, 9, false, 3]
[5, Kocourková Eva, nil, nil, false, 6]
[6, Kocourek Tomáš, nil, nil, true, 5]
[7, Mašek Jan, 8, 9, true, nil]
[8, Mašková Marie, nil, nil, false, 9]
[9, Mašek Ivan, nil, nil, true, 8]