#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>;

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