भवन्ति शशिनो मासाः सूर्येन्दुभगणान्तरम्। रविमासोनितास् ते तु शेषाः स्युर् अधिमासकाः ॥
The number of Lunar months is equal to the difference between the revolutions of the Moon and those of the Sun; and the remainder of the Lunar Months lessened by the Solar months is the number of Adhimásas (additive months.)
english translation