#include <iostream>
#include <iomanip>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <math.h>
#include <sstream>
#include <numeric>
#include <string>
#include <cassert>
#include <bitset>

using namespace std;
typedef long long ll;

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