Long term capital gains on immovable property

Land purchase fy 1963 -64 and construction completed before 1stApil 2001 . At the present time before sale of Immovable Property construction demolished and sale only land . Computation of Long term capital gains only basis of land cost as on 1st April 2001 or both land or construction cost of 1st April 2001 . Please advise on this point.