Relief u/s 89

sirs, i am a salaried employee. i had received salary for the FY 2015-16 april- sep 15 (rs 300000) in the fy 2015-16 itself. i had received salary for (oct - feb 16) rs. 350000 in FY 2016-17 only. i had not received anything for the fy 2016-17 in fy 2016-17 except 2015-16 arrears rs .350000. in fy 2017-18 i have received arrear salary - mar 16 -50000 , april 16- mar 17 - 750000, and fy 2017-18 salary -8 00000. while calculating relief under section 89 (1) when bifurcating arrears into various financial years which amount to takes as total income of the previous years excluding arrears received in current year ? 2015-16 - 650000 or 300000 ? 2016-17 - 350000 or nil ? pls advice me