Calculation of long term capital gain

Suppose I invest Rs10000 in equity mutual fund in April, 2015. The fund declares dividend but that is again invested to purchase units of the mutual fund (called "dividend reinvestment" option). Thus declared amount of dividend on June, 2015 is Rs1500, July 2016 is Rs1900 and Rs 2100 in July 2017, which are all invested. I redeem all units of the fund inn December 2017 at Rs 15000. Now if I calculate Long term capital gains from sale of fund units as: Rs(15000-10000-1500-1900)=Rs1600. Will that be correct? Also I guess there won't be any long term capital gains tax payable in this case for AY 2017-2018. Please comment if I am correct in these two cases.