#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ll long long
int main(){
    ll n;
    cin >> n;
    ll ans =0;
    for(ll i=1; i<=n; i++){
        if(i%3 != 0 && i%5 != 0) ans += i;
    }
    cout << ans << endl;
}