#include <iostream>
#include <string>
#define rep(i,n) for(long long i=0;i<n;i++)

using namespace std;
using ll = long long;

int main(void)
{
    ll n;
    cin >> n;
    ll sum=0;
    rep(i,n)
    {
        if((i+1)%3!=0  && (i+1)%5!=0) sum+=i+1;
    }
    cout << sum << endl;
    return 0;
}
