#include <bits/stdc++.h>
using namespace std;
int main(){
  int64_t N;
  cin >> N;
  int64_t sum = 0;
  for (int i=0;i<N;i++){
    if (i % 3 == 0){
      continue;
    }
    else if (i % 5 == 0){
      continue;
    }
    else;sum += i;
  }
  cout << sum << endl;
}