#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
ll n;
ll ans;
int main(void){
    cin>>n;
    for(int i=1;i<=n;i++){
        if(i%3!=0&&i%5!=0) ans+=i;
    }
    cout<<ans<<endl;
    
}
