#include<iostream>
#include<string>
#include<vector>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
using ll=long long;
const ll INF=1LL<<60;


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

  return 0;
}

