
#include <bits/stdc++.h>
using namespace std;
#define pp pair<int,int>
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define ll long long
#define ld long double
#define all(a) (a).begin(),(a).end()
#define mk make_pair
ll mod=998244353;
int inf=1000001000;
ll INF=1e18+5;
ll MOD=1000000007;
 
int main() {
    ll n;
    cin >> n;
    ll ans=0;
    for (ll i=1;i<=n;i++){
        if (i%3!=0 && i%5!=0) ans+=i;
    }
    cout << ans << endl;
}