function attachEventsListeners() {
    Array.from(document.querySelectorAll('[type="button"]')).forEach((b) => b.addEventListener('click', onClick));

    const buttons = {
        daysBtn: (i) => Number(i) * 24 * 60 * 60,
        hoursBtn: (i) => Number(i) * 60 * 60,
        minutesBtn: (i) => Number(i) * 60,
        secondsBtn: (i) => Number(i),
    };

    function onClick(e) {
        const input = e.target.previousElementSibling.value;
        const seconds = buttons[e.target.id](input);

        const minutes = seconds / 60;
        const hours = minutes / 60;
        const days = hours / 24;

        document.getElementById('days').value = days;
        document.getElementById('hours').value = hours;
        document.getElementById('minutes').value = minutes;
        document.getElementById('seconds').value = seconds;
    }
}