#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
int main(){
  long long int N;
  cin >> N;
  long long int sum = 0;
  for (int i=1; i<=N; i++){
    if (i%3 == 0 || i%5 == 0){
      sum = sum+0;
    }
    else sum += i;
  }
 cout << sum << endl;
}