#include<iostream>
#define rep(i, n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int, int>;
 
int main() {
    ll n;
    cin >> n;
    ll res = 0;
    for(ll i = 1; i <= n; ++i){
        if(i % 3 == 0 || i % 5 == 0) continue;
        res += i;
    }
    cout << res << endl;
    return 0;
}