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

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