#225;nsh&#464;</i> almanac (玄始曆) (221 leap months in 600 years), p=6246 and q=505 in the <i>Zh&#232;nggu&#257;ng</i> almanac (正光曆) (186 leap months in 505 years), p=4836 and q=391 in the <i>D&#224;m&#237;ng</i> almanac (大明曆) created by Z&#468; Ch&#333;ngzh&#299; (144 leap months in 391 years), p=5306 and q=429 in the <i>K&#257;ihu&#225;ng</i> almanac (開皇曆) (158 leap months in 429 years), and so on. In this method, the congruence equations in (1) can be written as</p><p>N &equiv; R<su