LTCG HOUSE TAX

KINDLY////   PLEASE GIVE 2 MINUTES TO UNDERSTAND THEN ANSWER.................................................I had sold house  No 1 .... in  October 2018 in which i had Capital Gain/ LTCG of Rs 75 Lakh in September 2018 i purchases new house (ie No 2)  ......for Rs 90 Lakh and got exemption U/S 54 OF IT Act of Rs 75 Lakh tax.................................But now i am getting offer by some one to sell same house No 2 for Rs 3 crores which i could sell in November  2020 or even in november 2021........................................so if i sold this house ,  so what would be my tax liabity ( of exemption of Rs 75 lakhs, its possible or is it compulsoryily i have to hold for 3 years) as i am selling house No 2 . in november 2020 or november 2021.........................................and what if i purchase new house no 3 after selling the said house no 2