Translate to Czech:

This took place on the day of Pentecost when they were together in prayer in the Upper Room with the Virgin Mary.

Czech:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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To se uskutečnilo v den Letnic, když byli učedníci shromážděni ve večeřadle při modlitbě spolu s Pannou Marií.