Rsa97

find /каталог ! -name \*.txt -type f -delete && find /каталог -type d -empty -delete

function addLetters(...letters) {
  if (letters.length == 0) {
    return 'z';
  }
  let sum = letters.reduce(
    (acc, val) => {
      let newAcc = acc + val.charCodeAt(0) - 96;
      return newAcc > 26 ? newAcc - 26 : newAcc;
    },
    0
  );
  return String.fromCharCode(sum + 96);
}