The insane person must tame their mind by thorough means.
‘The counting stage, when the attention is fixed on the “point of touch” and the attempt is made to make that attention strong and firm by the method of counting, is the first stage of the first tetrad of the Pāḷi Text. In this stage, the main work is to overcome the habit of the mind that repeatedly wanders away from the point of attention to other objects, and it is for this purpose that the method of counting is adopted. The time is not yet ripe for perceiving the long and short breaths, but in accordance with the Pāḷi Text — “Satova Assasati, Satova Passasati” — effort must be confined to keeping the attention fixed on the out-breath and in-breath.
Herein, this is what the Commentary says: “For counting is simply a device for settling“Bahivisaṭavitakkavicchedaṃ katvā assāsapassāsārammaṇe sati samthaṇṭhāpanaṭṭhaṃ yeva hi gaṇanā”ti. mindfulness on the in-breaths and out-breaths as object by cutting off the external dissipation of applied thoughts.” (Vism.280) Ledi Sayadaw