Ltcg on sale of land & building

A land was purchsed for Rs 10 lakhs in FY 2005-06 and the construction on it was commened in FY 2015-16 which was completed in FY 2016-17. The cost of construction on it was Rs 20 Lakhs. Further during the FY 2016-17, the assessee sold the building (along with land) for Rs 50 Lakhs. What shall be its tax treatment, whether there will be STCG or LTCG. Further, how shall the LTCG/STCG be determined?