how to root htc desire 816 running on Lollipop

i have recently updated my HTC desire 816 to lollipop. I unlocked the bootloader and tried to root it. but it . it says that it has been updated to lollipop, so i have to use manual method of rooting.


i couldnt succeed using manual method. should i downgrade it to kitkat to root it successfully??


I am stuck. there are too many bloatwares and i am running out of internal memory :(