nareshchilukuru

# One copy of any of the five books costs 8 EUR. If, however, you buy two
# different books from the series, you get a 5% discount on those two books.
# If you buy 3 different books, you get a 10% discount. With 4 different
# books, you get a 20% discount. If you go the whole hog, and buy all 5, you
# get a huge 25% discount.

# Note that if you buy, say, four books, of which 3 are different titles, you
# get a 10% discount on the 3 that form part of a set, but the fourth book
# still costs 8 EUR.