#include <bits/stdc++.h>
using namespace std;
#define ll long long


int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    int n;
    cin>>n;
    ll sum = 0;
    for(int i=1;i<=n;++i)
    {
        if(i%3!=0 && i%5!=0 ) sum+=i;
    }
    cout<<sum;
}
