#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define endl "\n"
#define deb(x) cerr << #x << ":" << x << "\n"

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

int main()
{

    ios::sync_with_stdio(0);
    cin.tie(0);
    ll t=1;
    // cin>>t;
    while(t--){
        solve();
    }
    return 0;
}
