#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <map>
#include <set>
#include <cassert>

#define rep(i,x) for(int i = 0; i < x; i++)
#define rrep(i,x) for(int i = 1; i <= x; i++)
#define srep(i,s,t) for (int i = s; i < t; ++i)
using ll = long long;
using namespace std;
const int INF = 1001001001;
const ll LINF = 1002003004005006007;

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