/*
 * Author: Anmol Choudhary
 */
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include<bits/stdc++.h>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
#define pb push_back
#define vi vector<int>
#define rep0(a,b) for(int a=0;a<b;a++)
#define rep1(a,b) for(int a=1;a<=b;a++)
#define repp(a,b,c) for(int a=b;a<c;a++)
#define in insert
#define len length()
#define si size()
#define lb lower_bound
#define ub upper_bound
#define beg begin()
#define en end()
#define f first
#define s second
#define pr(a) cout<<a
#define pr2(a,b) cout<<a<<" "<<b<<"\n"
#define nx cout<<"\n"
#define int long long
const ll mod = 1000000007;
const ll maxn = 500005;
const ll mm = 1e+18;
void solve()
{
    int n;
    cin>>n;
    int an=0;
    rep1(i,n){
        if(i%3&&i%5) an+=i;
    }
    pr(an);
}
signed main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int t=1;
    //cin>>t;
    while(t--){
        solve();
        //nx;
    }
    return 0;
}
