#include<bits/stdc++.h>
#define int int64_t
using namespace std;

const int M = 1e9+7;

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n;
    cin >> n;
    int sum = 0;
    for(int i = 1; i <= n; i++) {
        if(i % 3 == 0 && i % 5 == 0) continue;
        if(i % 3 == 0 && i % 5 != 0) continue;
        if(i % 3 != 0 && i % 5 == 0) continue;
        sum += i;
    }
    cout << sum << "\n";

    return 0;
}
