#include<iostream>
using namespace std;
 
int main(int, char**)
{
    int n;
 
    cin >> n;
 
    long long result = 0;
    for (int i = 1; i <= n; i++)
        if (i % 3 != 0 && i % 5 != 0) result += i;
 
    cout << result << endl;
 
    return 0;
}