discounts = { 1: 1, 2: 0.95, 3: 0.90, 4: 0.80, 5: 0.75, }

def get_price(books):
    sets = []
    for book in books:
        for set in sets:
            if book not in set:
                set.append(book)
                break
        else:
            sets.append([book])

    total_price = 0
    for set in sets:
        total_price += (len(set) * 8) * discounts[len(set)]

    return total_price