import java.util.Scanner;

class Test {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.next();
        int n = Integer.parseInt(str);
        long z = 0;
        
        for(int i = 1; i <= n; i++) {
            if(i % 3 == 0) {
                if(i % 5 == 0) {
                    //FizzBuzz
                    z = z + 4;
                } else {
                    //Fizz
                    z = z + 2;
                }
            } else if(i % 5 == 0) {
                //Buzz
                z = z + 2;
            } else {
                continue;
            }
        }
        
        System.out.println(z);
    }
}