#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;

    long long ans = 0;
    for(int i = 1; i <= n; i++) {
        if(i % 3 != 0 && i % 5 != 0) ans += (long long)i;
    }

    cout << ans << endl;
    
    return 0;
}