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

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