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

int main()
{
    int n;
    ll out=0;

    cin >> n;

    for (int i=1;i<=n;++i){

        if (!(i%3==0 || i%5==0))out+=i;

    }

    cout << out << endl;
    return 0;
}