#include <bits/stdc++.h>
#define ll long long
#define V vector<long long>
#define VV vector<vector<long long>>
#define rep(i,n) for(ll (i)=0;(i)<(n);++(i))
using namespace std;

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