Visiting cart
    Visiting apple
    Visiting banana
    Visiting apple
size of cart = 4
number of atoms of cart = 3
watermelon not found

Visiting wagon
    Visiting watermelon
    Visiting pumpkin
size of wagon = 3
number of atoms of wagon = 2
watermelon found at Item 5

Visiting train
    Visiting cart
        Visiting apple
        Visiting banana
        Visiting apple
    Visiting wagon
        Visiting watermelon
        Visiting pumpkin
size of train = 8
number of atoms of train = 5
watermelon found at Item 5