Hi Aldor, welcome to the forum

Hungary
Hungarian import mark for silver 1st standard 925/000, used 1999-2006. In 2006, the use of separate import marks was discontinued. All articles, both import and domestic, were stamped with the same domestic hallmark.
The A is a date letter. Beginning in 1999 Hungary introduced a date letter, which may periodically be changed by an official decree at the discretion of the Hungarian Parliament. A capital letter A was the date letter used from 1999 to the end of 2005, while the letter B started in 2006.
Peter.
Source;
World Hallmarks Volume I Europe Hallmark Research Institute 2nd Edition, Whetstone, Niklewicz, Matula. Page134