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

int main() {
  int64_t N;
  cin >> N;
  int64_t sum = 0;
  for(int i = 1;i <= N;i++){
    if(i % 3 == 0 || i % 5 == 0){
      continue;
    }
    
    sum += i;
  }
  
  cout << sum << endl;
  
}
