var firstName = "Charles" usando firstName[firstName.length - 3] lastName . Insinuación thirdToLastLetterOfFirstName si te quedas atascado. secondToLastLetterOfLastName debe ser "c".
    testString: 'assert(secondToLastLetterOfLastName === "c", "secondToLastLetterOfLastName should be "c".");'
  - text: Tienes que usar .length para obtener la segunda última letra.
    testString: 'assert(code.match(/\.length/g).length === 2, "You have to use .length to get the second last letter.");'
```