HUD total ammo

I was wondering how you would display the total ammo? I know how to display how much ammo is in the weapon currently, and in clip 2, but not total ammo. For example)
You have 1000 bullets left for your pistol
You want the HUD to say 18 / 1000

18 being amount in the mag that is in the gun and 1000 being how much total ammo you have left for the gun. Here is my code for my Ammo HUD Text:
[lua]
local wep = LocalPlayer():GetActiveWeapon()
if wep and wep:IsValid() then
draw.SimpleText( "Ammo: " … wep:Clip1() … " / " … wep:Clip2(), “Trebuchet24”, ScrW() * 0.4275, ScrH() * 0.965, tcolor )[/lua]

[lua]
local wep = LocalPlayer():GetActiveWeapon()
if wep and wep:IsValid() then
local Ammo = LocalPlayer():GetAmmoCount(wep:GetPrimaryAmmoType())
draw.SimpleText( "Ammo: " … wep:Clip1() … " / " … Ammo, “Trebuchet24”, ScrW() * 0.4275, ScrH() * 0.965, tcolor )
end
[/lua]
I havent tested it.

Thank you Dragge, it worked.