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

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