#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;
const ll INF = ll(1e18)+1;

int main(){
  int n;
  cin >> n;
  ll ans = 0;
  for(int i=1;i<=n;i++){
    if(i%3==0 || i%5==0)continue;
    ans += i;
  }
  cout << ans << endl;
}