function factorial(input) {
return 2* input;

}

document.addEventListener('DOMContentLoaded', () => {
    let list = document.querySelector(".list");
    for(let i = 0; i < 8; i++) {
      let element = document.createElement("LI");
        element.innerText = i+1;
        element.classList.add(`list-elem-${i+1}`);
        if(i === 5) {
          element.addEventListener('click', () => {
            element.innerText = factorial(i+1);
          });
        } else if(i === 7) {
          element.addEventListener('click', () => {
           element.style.backgroundColor = '#ececec';
           element.style.color = '#00ff00';
          });
        }
      list.appendChild(element);
    }
  });