Manava Dharmashastra 11.192

11.192

prāyaścittaṃ cikīrṣanti vikarmasthās tu ye dvijāḥ
brahmaṇā ca parityaktās teṣām apy etad ādiśet //

Those twice-born men who may not have been taught the Savitri (at the time) prescribed by the rule, he shall cause to perform three Krikkhra (penances) and afterwards initiate them in accordance with the law.