#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const ll MOD=(ll)1e9+7;
const ll MOD2=(ll)998244353;
const ll INF=(ll)1e18+10;
const double PI=acos(-1);

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 (a>b) { a=b; return 1; } return 0; }
int dy[]={-1,1,0,0};
int dx[]={0,0,-1,1};

void solve(int ca){
    int N; cin>>N;
    ll ans = 0ll;

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

}

//#define MULTI
int main() {
#ifdef MULTI
    int N; cin>>N;
    for (int i = 0; i < N; ++i) {
        solve(i+1);
    }
#else
    solve(1);
#endif
    return 0;
}
