Hungarian has seven short vowels (a, e, i, o, u, acute accent (?/A>, ? ?/A>, ?/A>, ?/A>). (The accented a and e is not really just a longer version but articulated differently.)
The double acute acts as combined acute with umlaut, giving the longer version of ?/em> and ?/em>.
The codes are supported in the ISO 8859-2 and UTF-8 codepages, the letters are:
ő U0151 latin small letter o with double acute
ű U0171 latin small letter u with double acute
Ő U0150 latin capital letter o with double acute
Ű U0170 latin capital letter u with double acute