Mantra 4

निधनमिति त्र्यक्षरं तत्सममेव भवति तानि ह वा एतानि द्वाविंशतिरक्षराणि ॥ २.१०.४ ॥

In plain words

Nidhana has three syllables, and that too is equal. These make twenty-two syllables in all.