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

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