#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn = 1e5 + 5;
int main()
{
    ios::sync_with_stdio(false);
    int 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;
}
