#include <iostream>

using namespace std;

int main()
{
    int n;
    long long sum=0;
    cin >> n;
    for(int i=1;i<=n;i++)
    {
        if(i%3==0 || i%5==0)
            continue;
        sum+=i;
    }
    cout << sum << endl;
    return 0;
}
