/**
 * 验证IP地址
 * @param IP string字符串 一个IP地址字符串
 * @return string字符串
 */
function solve(IP) {
  // write code here
  const arr4 = IP.split(".");
  const arr6 = IP.split(":");
  const ex4 = /^0$|^[1-9]\d{0,2}$/;
  const ex6 = /^[0-9a-fA-F]{1,4}$/;
  if (arr4.length == 4 && arr4.every((item) => item.match(ex4) && item < 256)) {
    return "IPv4";
  } else if (arr6.length == 8 && arr6.every((item) => item.match(ex6))) {
    return "IPv6";
  }
  return "Neither";
}
module.exports = {
  solve: solve,
};