#include <iostream>
#include <cstdlib>
#include <utility>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <cmath>
#include <numeric>

using namespace std;
using ll = long long;

#define loopi(i, a, b) for(int i = (int)a; i < (int)b; i++)
#define loop(i, n) for (int i = 0; i < (int)n; i++)
#define loopeq(i, n) for (int i = 0; i <= (int)n; i++)
#define loopll(i, n) for (ll i = 0; i < (ll)n; i++)
#define looplleq(i, n) for (ll i = 0; i <= (ll)n; i++)

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