He [R' Akiva] would also say: There are five things that are of twelve months' duration: The judgment of the Generation of the Flood [was administered over a period of] twelve months.  The judgment of Job [was over] twelve months.  The judg-ment of the Egyptians [was over] twelve months.  The judgment of Gog and [his nation] Magog in the Future to Come [will occur over a period of] twelve months.  And the judgment of evildoers in Gehinnom [endures for] twelve months, as it is stated: And it will be from a month to its month. R' Yochanan ben Nuri says: [The judgment of evildoers takes place] from Pesach to Shavuos, as it is stated: from a Sabbath to its Sabbath.