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 Rust (1.42.0) (judge verdict: Accepted)

fn main() {
    println!("{}", solve(input()));
}

fn input() -> u64 {
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).unwrap();
    buf.pop();

    let n: u64 = buf.parse().unwrap();
    n
}

fn solve(n: u64) -> u64 {
    let all_sum = n * (n + 1) / 2;
    let sum_3 = ((n/3) * ((n/3)+1) / 2) * 3;
    let sum_5 = ((n/5) * ((n/5)+1) / 2) * 5;
    let sum_15 = ((n/15) * ((n/15)+1) / 2) * 15;

    all_sum - (sum_3 + sum_5 - sum_15)
}