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

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