text: const inputRef = document.querySelector('#validation-input');
  const numberСharacters = Number(inputRef.dataset.length);
  
  inputRef.addEventListener('blur', checkNumberCharacters);
  
  function addClassValid(event) {
    event.target.classList.add('valid');
  }
  function removeClassInValid(event) {
    event.target.classList.remove('invalid');
  }
  
  function addClassInValid(event) {
    event.target.classList.add('invalid');
  }
  function removeClassValid(event) {
    event.target.classList.remove('valid');
  }
  function checkNumberCharacters(event) {
    const numberСharactersInInput = event.target.value.length;
    if (numberСharactersInInput === numberСharacters) {
      addClassValid(event);
      removeClassInValid(event);
    } else {
      addClassInValid(event);
      removeClassValid(event);
    }
  }
  