#include <bits/stdc++.h>

using namespace std;

int main()
{
    string S;
    int N;
    cin >> N;
    long long ans = 0;
    for (int i = 1; i <= N; i++)
    {  
        if(i%3 == 0|| i%5 ==0) continue;
        ans += i;
    }
    cout << ans << endl;
}
