#include <iostream>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)

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