Display total amount of discount in the cart

-- HikaShop version -- : 3.0.1
-- Joomla version -- : 3.6.5

hi,
in checkout cart and cart status view i want to add the total amount of discount used in the cart next to Total amount of purchased!
for example if a user purchased 5 item with 200$ on each product and used 50$ discount for each iwant this to show:

total: 1000$
total discount: 250$
u can pay: 750$

i think i have to add come codes in Show_Block_Cart in Checkout and i appreciate if you can help me do this.

thanks

Hi Nicolas,
yes, i know that, and i even know the exact place to where to place the code
i only want a line of code that can echo sum of discounts.

i'm running out of time, and hiring an expert need lots of it.
i'll be appreciative if u can give the exact code. or an example or ...