#include <bits/stdc++.h>
using namespace std;
#define SORT(a) sort((a).begin(), (a).end())
#define RSORT(a) reverse((a).begin(), (a).end())
#define rep(i, n) for (int i = 0; i < n; i++)
typedef long long ll;
const long long INF = 1LL << 60;
// const int INF=1010101010;
using Graph = vector<vector<int>>;

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