#include <bits/stdc++.h>
using namespace std;

int main() {
    int64_t N;
    cin >> N;
    int64_t ans=0;

    for(int64_t i=1;i<=N;i++){
        if(i%3!=0&&i%5!=0)ans+=i;
    }

    cout << ans << endl;

    return 0;
}
