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