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 C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;


    class MainClass
    {
    public static void Main(string[] args)
    {

        int N = int.Parse(Console.ReadLine());


        long sum = (1 + N) * N / 2;

        int a = N / 3;

        long b = 3 * (1 + a) * a / 2;

        int c = N / 5;

        long d = 5 * (1 + c) * c / 2;

        int e = N / 15;

        long f = 15 * (1 + e) * e / 2;


        sum = sum - b - d + f;


        Console.WriteLine(sum);


    }
}