#include <bits/stdc++.h>
#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() {
    int n;
    cin >> n;

    ll sum=0;

    rep(i,n) {
        if ((i % 3 != 0) && (i%5 != 0)) {
            sum += i;
        }
    }

    cout << sum << endl;




    return 0;
}

