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

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


