#include <iostream>

using namespace std;

int
main()
{
    uint64_t n;
    cin >> n;

    uint64_t ans = 0;

    for(int i=1;i<=n;i++){
        if((i%3 == 0) ||
           (i%5 == 0)){
            continue;
        }

        ans += i;
    }

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