# https://projecteuler.net/problem=01
# If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
# Find the sum of all the multiples of 3 or 5 below 1000.

x = set(range(3,1000,3))
y = set(range(5,1000,5))

print(sum(x|y))