#include <bits/stdc++.h>
#define FAST ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ll long long

using namespace std;


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