#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> mp;
ll inf =  1e9;


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