#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
int main()
{
    ll n;
    cin>>n;
    ll sum=0;
    for(int i=1;i<n;i++)
    {
        if(i%3==0 || i%5==0)
        {
            continue;
        }
        else
        {
            sum+=i;
        }
    }
    cout<<sum<<"\n";
}
