function solve() {
  let inputArr = Array.from(document.querySelectorAll("form input"));
  let totalSum=0;

  let addButton = document.querySelector("form button");
  addButton.addEventListener("click", addBook);

  let newBookShelf = Array.from(
    document.querySelectorAll("#outputs section")
  )[1].lastElementChild;
  let oldBookShelf = Array.from(
    document.querySelectorAll("#outputs section")
  )[0].lastElementChild;

  function addBook(ev) {
    ev.preventDefault();

    let title = inputArr[0].value;
    let year = +inputArr[1].value;
    let price = +inputArr[2].value;

    if (title && year > 0 && price > 0) {
      if (year >= 2000) {
        let wrapper = document.createElement("div");
        wrapper.setAttribute("class", "book");

        let p = document.createElement("p");
        p.textContent = `${title} [${year}]`;

        let addButton = document.createElement("button");
        addButton.textContent = `Buy it only for ${price.toFixed(2)} BGN`;
        addButton.addEventListener('click',function(){
            totalSum+=price;
            Array.from(document.querySelectorAll('h1'))[1].textContent=`Total Store Profit: ${totalSum.toFixed(2)} BGN`;
            newBookShelf.removeChild(wrapper);
        });

        let moveButton = document.createElement("button");
        moveButton.textContent = "Move to old section";

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

            let updatedWrapper=document.createElement("div");
            updatedWrapper.setAttribute("class", "book");

            let updatedP=document.createElement("p");
            price = price - price * 0.15;
            updatedP.textContent = `${title} [${year}]`;

            let uppdatedButton = document.createElement("button");
            uppdatedButton.textContent = `Buy it only for ${price.toFixed(2)} BGN`;
            uppdatedButton.addEventListener('click',function(){
            totalSum+=price;
            Array.from(document.querySelectorAll('h1'))[1].textContent=`Total Store Profit: ${totalSum.toFixed(2)} BGN`;
            oldBookShelf.removeChild(updatedWrapper);
          });
          updatedWrapper.appendChild(updatedP);
          updatedWrapper.appendChild(uppdatedButton);

          newBookShelf.removeChild(wrapper);
          oldBookShelf.appendChild(updatedWrapper);

        });

        wrapper.appendChild(p);
        wrapper.appendChild(addButton);
        wrapper.appendChild(moveButton);
        newBookShelf.appendChild(wrapper);

      } else {
        let wrapper = document.createElement("div");
        wrapper.setAttribute("class", "book");

        let p = document.createElement("p");
        price = price - price * 0.15;
        p.textContent = `${title} [${year}]`;

        let addButton = document.createElement("button");
        addButton.textContent = `Buy it only for ${price.toFixed(2)} BGN`;
        addButton.addEventListener('click',function(){
            totalSum+=price;
            Array.from(document.querySelectorAll('h1'))[1].textContent=`Total Store Profit: ${totalSum.toFixed(2)} BGN`;
            oldBookShelf.removeChild(wrapper);
        });
        wrapper.appendChild(p);
        wrapper.appendChild(addButton);
        oldBookShelf.appendChild(wrapper);
      }
    }
  }
}