function solve() {
    let buttons = document.getElementsByTagName('button');
    let nextBtn = buttons[0];
    nextBtn.addEventListener('click', nextEvent);
    let cancelButton = buttons[1];
    cancelButton.addEventListener('click', cancelEvent);
    let currentStep = -1;
    let steps = document.getElementById('content').children;

    function nextEvent () {

        document.getElementById('content').style.backgroundImage = 'none';

        if (currentStep === 0) {
            let disagreeBtn = document.getElementById('firstStep').getElementsByTagName('input')[1];

            if (disagreeBtn.checked) {
                return;
            }

            nextBtn.style.display = 'none';

            setTimeout(() => {
                nextBtn.style.display = 'inline';
            }, 3000)
        }

        if (currentStep === 1) {
            nextBtn.style.display = 'none';
            cancelButton.textContent = 'Finish';
        }

        if (currentStep !== -1) {
            steps[currentStep].style.display = 'none';
        }

        if (currentStep === 2) {
        document.getElementById('exercise').getElementsByTagName('section')[0].style.display = 'none';
        }

        currentStep++;

        steps[(currentStep)].style.display = 'block';
    }

    function cancelEvent () {
        document.getElementById('exercise').getElementsByTagName('section')[0].style.display = 'none';
    }
}