56. For the purposes of this chapter, the actual cost to an individual at a given time after 1971, of a share owned by him on 31 December 1971 and thereafter without interruption until that given time and which is acquired by him in a taxation year prior to 1972 in accordance with an agreement contemplated by section 114 of the former Tax Act respecting individuals is equal to the greater of its fair market value at the time when he has so acquired it or its actual cost, to him, computed without taking account of this section.