#include <bits/stdc++.h>
#define rep(i,n) for (int i=0;i<(n);++i)
using namespace std;
using ll = long long;

int main() {
  int n;
  ll s=0;

  cin >> n;

  rep(i,n+1) {
    if ((i%3==0)||(i%5==0)) continue;
    else s+=i;
  }
  cout << s << endl;
}