#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
using namespace std;
const int INF = 100000000;
const int MAX_N = 100;
typedef pair<int , int> P;
typedef long long ll;

int main() {
  int N;
  cin >> N;
  ll ans = 0;
  for (int i = 1; i <= N; ++i) {
    if (i % 3 != 0 || i % 5 != 0) {
      ans += i;
    }
  }
  printf("%lld\n", ans);
  return 0;
}
