Problem:
Score : 200 points

Problem Statement

Let us define the FizzBuzz sequence a_1,a_2,... as follows:

If both 3 and 5 divides i, a_i=\mbox{FizzBuzz}.

If the above does not hold but 3 divides i, a_i=\mbox{Fizz}.

If none of the above holds but 5 divides i, a_i=\mbox{Buzz}.

If none of the above holds, a_i=i.

Find the sum of all numbers among the first N terms of the FizzBuzz sequence.

Constraints

1 \leq N \leq 10^6

Input

Input is given from Standard Input in the following format:

N

Output

Print the sum of all numbers among the first N terms of the FizzBuzz sequence.

Sample Input 1

15

Sample Output 1

60

The first 15 terms of the FizzBuzz sequence are:

1,2,\mbox{Fizz},4,\mbox{Buzz},\mbox{Fizz},7,8,\mbox{Fizz},\mbox{Buzz},11,\mbox{Fizz},13,14,\mbox{FizzBuzz}

Among them, numbers are 1,2,4,7,8,11,13,14, and the sum of them is 60.

Sample Input 2

1000000

Sample Output 2

266666333332

Watch out for overflow.

Solution in Python (3.8.2) (judge verdict: Wrong Answer)

def main():
    n = int(input())
    a, b = n // 15, n % 15

    fbeg = [i for i in range(1, 16) if i % 3 != 0 and i % 5 != 0]
    fend = [i for i in range(a * 15, n + 1) if i % 3 != 0 and i % 5 != 0]

    ne = len(fbeg)
    fbs = sum(fbeg) # sum of first terms in [1, 15]
    fes = sum(fend)
    step = 15 * ne
    first = fbs
    last = fbs + (a-1) * step

    tot = (first + last) * (last - first + step) // step // 2 + sum(fend)

    print(tot)