#include<bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
typedef long long ll;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n;
    cin >> n;
    ll sum = 0;
    for(int i = 1; i <= n; ++i)
        if(i%3 == 0 || i%5 == 0);
        else
            sum += i;
    cout << sum;
    return 0;
}
