#include <iostream>
#include <bits/stdc++.h>
using namespace std;
using ll = int64_t;
#define rep(i,n) for(int i = 0; i < ((int)(n)); i++)   // 0-indexed昇順

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