Instructions: This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.
Input: Passage: Zrinski and Frankopan were executed by beheading on 30 April 1671 in Wiener Neustadt. Their estates were confiscated and their families relocated Zrinski's wife, Katarina Zrinska, was interned in the Dominican convent in Graz where she fell mentally ill and remained until her death in 1673, two of his daughters died in a monastery, and his son Ivan Antun died in madness, after twenty years of terrible imprisonment and torture, on 11 November 1703. The oldest daughter Jelena, already married in northeastern Upper Hungary, survived and continued the resistance. Some 2,000 other nobles were arrested as part of a mass crackdown. Two more leading conspirators Ferenc Nadasdy, Chief Justice of Hungary, and Styrian governor, Count Hans Erasmus von Tattenbach were executed . In the view of Emperor Leopold, the Croats and Hungarians had forfeited their right to self-administration through their role in the attempted rebellion. Leopold suspended the constitution - already, the Zrinski trial had been conducted by an Austrian, not a Hungarian court - and ruled Hungary like a conquered province.
Question: How many years after his mother did Ivan Antun die?
Answer type: Number
Output:
30.