import re
def rot13(text: str) -> str:
    ans = ""
    for letter in text:
        if not re.fullmatch(r"[a-zA-Z]", letter):
            ans += letter
            continue
        ascii_value = ord(letter)
        new_value = ascii_value + 13
        is_upper = ascii_value >= 65 and ascii_value <= 90
        if (is_upper and new_value > 90) or (not is_upper and new_value > 122):
            new_value -= 26
        ans += chr(new_value)
    return ans