//
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ar array
#define vec vector 


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

int main(){
    solve();
}

