#include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using db = double;
using pii = pair < int, int >;
using pll = pair < ll, ll >;
const int N = 2e5 + 10;
const ll inf = 1e15 + 42;
#define endl "\n"
const ll mod = 1000000007;
 
void testCase() {
    ll n;
    cin >> n;
    ll sum = 0;
    for (int i=1; i<=n; i++) {
        if (i%3==0 || i%5==0)
            continue;
        sum += i;
    }
    cout << sum << endl;
}
 
int main() {
    ios_base :: sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    testCase();
    return 0;
}