# Arup Guha
# 4/8/2020
# New Set Exercise
# Simulation. You start with some items. Groups come looking for donations.
# You give them everything they want that you have.
# At the end, we print out what you have left.

def main():

    # Set up your set.
    print("Please enter all items you have, 1 per line, type end on the last line.")
    myitems = set()

    # Get first item.
    item = input()

    # Add each item until the end.
    while item != "end":
        myitems.add(item)
        item = input()

    ans = input("Is there someone who is coming for donations?\n")

    # Keep on going until there are no more donations.
    while ans[0] == 'y' or ans[0] == 'Y':

        # Set up donation set.
        print("Please enter the items you are looking for, 1 per line, type end on the last line.")
        look = set()

        # Add all items.
        item = input()
        while item != "end":
            look.add(item)
            item = input()

        # Subtract out all items in myitems that are also in look.
        myitems = myitems - look

        # Get next donation.
        ans = input("Is there someone who is coming for donations?\n")

    # Print out items left.
    print("Here are the items you have left:")
    for x in myitems:
        print(x)

# Go!
main()