#include <cstdio>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>

using namespace std;

typedef long long ll;

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;
  return 0;
}