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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleTest
{
    static partial class Program
    {

        static void Main(string[] args)
        {
            var n = Int();
            long sum=0;
            for(int i = 1; i <= n; ++i)
            {
                if (i % 3 == 0) continue;
                if (i % 5 == 0) continue;
                sum += i;
            }
            Console.WriteLine(sum);

        }

    }
    static partial class Program
    {
        public static int Int()
        {
            return int.Parse(Console.ReadLine());
        }
        public static int[] Ints()
        {
            return Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToArray();
        }
        public static long[] Longs()
        {
            return Console.ReadLine().Split(' ').Select(s => long.Parse(s)).ToArray();
        }
        public static int[][] MultiInts(int num)
        {
            var result = new int[num][];
            for(int i = 0; i < num; ++i)
            {
                result[i] = Ints();
            }
            return result;
        }
        public static T[] MultiItems<T>(int num, Func<string,T> parser)
        {
            var result = new T[num];
            for(int i =0; i < num; ++i)
            {
                result[i] = parser(Console.ReadLine());
            }
            return result;
        }
    }
}