#include <bits/stdc++.h>
#define rep(i,n) for(int i=1; i<=(n); ++i)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main(){
    ll n;
    cin >> n;

    ll sum = 0;
    rep(i,n){
        if(i%3!=0 && i%5!=0){
            sum+=i;
        }
    }

    cout << sum << endl;

    return 0;
}