उद्गीथ इति त्र्यक्षरमुपद्रव इति चतुरक्षरं त्रिभिस्त्रिभिः समं भवत्यक्षरमतिशिष्यते त्र्यक्षरं तत्समम् ॥ २.१०.३ ॥
In plain words
Udgītha has three syllables, upadrava has four syllables: with three each they are equal, and one syllable is left over; taken as three syllables, it is equal.