#include <bits/stdc++.h>
using namespace std;

int main() {
  int n; cin >> n;
  long long out = 0;
  for(int i = 1; i <= n; i++){
    if(i % 3 == 0) continue;
    if(i % 5 == 0) continue;
    out += i;
  }
  cout << out;
}
