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

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