Who is the only actor with whom Prem Chopra has done more than 20 films?

Prem Chopra and Rajesh Khanna did 20 films together including Do Raaste, Doli, Daag, Prem Nagar, Kati Patang, Awaaz, Zamana, Dharma Aur Kanoon, Ajnabee, Mahachor, Tyag, Mehbooba, Aanchal, Jaanwar, Sautan, Maksad.