#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define rep(i,n) for(ll i = 0; i < (ll)(n); i++)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll INF = 1LL << 60;
int main(){
    int n;
    cin >> n;
    ll ans = 0;
    rep(i,n){
        if(i%3!=0 && i%5!=0) ans+=i;
    }
    cout << ans << endl;
    return 0;
}