function timeConversion(s) {
  // spit the time string into 3 parts
  // extract the letters from the 3rd part
  // in the 1st part, add 12 if its PM, and subtract 12 if its 12 pm
  // concatenate everything together

  const arr = s.split(":");
  const firstPart = arr[0];
  const secondPart = arr[1];
  const thirdPart = arr[2];
  const id = thirdPart.slice(-2);

  let newFirstPart = "";
  if (Number(firstPart) < 12 && id === "AM") {
    newFirstPart = firstPart;
  } else if (Number(firstPart) < 12 && id === "PM") {
    newFirstPart = formatTwoDigits(Number(firstPart) + 12);
  } else if (Number(firstPart) === 12 && id === "AM") {
    newFirstPart = formatTwoDigits(0);
  } else if (Number(firstPart) === 12 && id === "PM") {
    newFirstPart = firstPart;
  }

  return newFirstPart + ":" + secondPart + ":" + thirdPart.slice(0, 2);
}