function solve() {
   let fundamentals = Array.from(document.getElementsByTagName('input'))[0];
   let advanced = Array.from(document.getElementsByTagName('input'))[1];
   let applications = Array.from(document.getElementsByTagName('input'))[2];
   let web = Array.from(document.getElementsByTagName('input'))[3];

   let onSite = Array.from(document.getElementsByTagName('input'))[4];
   let online = Array.from(document.getElementsByTagName('input'))[5];

   let button = document.querySelector('.courseFoot button');

   let ul = Array.from(document.querySelectorAll('.courseBody ul'))[0];

   let fundPrice = 170;
   let advancedPrice = 180;
   let applicationsPrice = 190;
   let webPrice = 490;

   let totalCost = 0;

   button.addEventListener('click', function () {


      if (advanced.checked && fundamentals.checked) {


         advancedPrice *= 0, 9;
      }
      if (fundamentals.checked && advanced.checked && applications.checked) {


         fundPrice *= 0.94;
         advancedPrice *= 0.94;
         applicationsPrice *= 0.94;
      }
      if (fundamentals.checked && advanced.checked
         && applications.checked && web.checked) {

      }

      if(online.checked){
         fundPrice *= 0.94;
         advancedPrice *= 0.94;
         applicationsPrice *= 0.94;
         webPrice *= 0.94;
      }

      let counter = 0;

      let allChecked = Array.from(document.querySelectorAll('input:checked'));
      allChecked = allChecked.filter(x=>x.type !== 'radio');
      let ulMyCourses = document.querySelectorAll('.courseBody ul')[1];
      allChecked.forEach(x => {
         counter++;

         if (x.name == 'js-fundamentals') {
            totalCost += fundPrice;
         }
         if (x.name == 'js-advanced') {
            totalCost += advancedPrice;
         }
         if (x.name == 'js-applications') {
            totalCost += applicationsPrice;
         }
         if (x.name == 'js-web') {
            totalCost += webPrice;
         }
         let name = x.name;


            console.log(allChecked.length)
            let liMyCourses = document.createElement('li');
            liMyCourses.textContent = x.nextElementSibling.textContent.split(' - ')[0];
            liMyCourses.textContent = liMyCourses.textContent.split(' ').join('-');

            liMyCourses.setAttribute('name',name);
            ulMyCourses.appendChild(liMyCourses);
            if( allChecked.length === 4 && counter === 4){
               let bonusCourse = document.createElement('li');
               bonusCourse.textContent = 'HTML and CSS';
               ulMyCourses.appendChild(bonusCourse);
            }


      })
      let costElement = document.querySelector('.courseFoot p');
      costElement.textContent = `Cost: ${(Math.floor(totalCost)).toFixed(2)} BGN`;
   })





}