#include <bits/stdc++.h>

#define REP(i, n) for(int (i)=0;(i)<(n);++(i))
#define REPV(iter, v) for(auto (iter)=(v).begin(); (iter)!=(v).end();++(iter))
#define ALL(v) (v).begin(),(v).end()

#define MOD 1000000007

using namespace std;

typedef long long ll;

int main()
{
    ll N;
    cin >> N;
    ll ans = 0;
    for (int i = 1; i <= N; ++i)
    {
        if (!(i % 3 == 0 || i % 5 == 0)) ans += i;
    }

    cout << ans << endl;
}
