text: /**
   * @param {string} a
   * @param {string} b
   * @return {number}
   */
  
  const findLUSlength = (string1, string2) => { // eslint-disable-line
    // length not the same, the longest string must be the LUS string
    if (string1.length !== string2.length) {
      return string1.length > string2.length ? string1.length : string2.length;
    }
    // both string are same length
    // if both string is same, no longest, so -1
    // if strings are different, two longest subsequence has same length, so return length
    return string1 === string2 ? -1 : string1.length;
  };
  