inline bool IsAlNum(int c) {
  return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') ||
         (c >= 'a' && c <= 'z');
}
inline bool IsAlNum(int c) {
  return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') ||
         (c >= 'a' && c <= 'z');
}