#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <iomanip>
#include <random>
#include <cstdio>
#include <cmath>
#include <climits>
#include <map>
#include <queue>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (int) n; i++)

int main() {
    int n;
    cin >> n;
    ll sum = 0;
    for (int i = 1; i <= n; i++)
    {
        if (!(i%3==0 || i%5==0)) sum += i;
    }
    cout << sum << endl;
    return 0;
}