#include <bits/stdc++.h>
using namespace std;
 
int main() {
  unsigned long long  N;
  unsigned long long result=0;

  cin >> N;

  for(int i=1; i <= N ;i++){
  
    if((i % 3 ==0)||(i % 5 ==0)){
    }else{
      result += i;
    }
  }

  cout << result << endl;
}