#include<bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i, n) for(int i = 0; i < (n); ++i)
using namespace std;
typedef long long ll;
template<class T> istream& operator >> (istream& s, vector<T>& v)
{ for (T& x: v) { s >> x; } return s;}
void yes(){ cout << "Yes" << endl; }
void no(){ cout << "No" << endl; }

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;
    return 0;
}
