# 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.

totalSum = 0

for number in range(1, 1000):
    if number % 3 == 0:
        totalSum += number
    elif number % 5 == 0:
        totalSum += number
    else:
        pass

print(totalSum)