How many years can a person's birthday be reunited with the solar calendar? Please, thank you.

The number of days in the solar year is not an integer, 365 is followed by a decimal, and it is irrational. The number of days in the lunar calendar is not exactly 29.5, and there is also a long string of decimals behind it. Therefore, it is impossible to ask for a real common multiple of the number of days in the lunar calendar and the number of days in the solar calendar. The leap in the calendar is only coordinated to a certain extent, which is why the calendar was frequently revised in ancient times. The seventh leap in the 19th year of the lunar calendar is only an approximate formulation, and it should be set at 1.