how do i check how many of a tool is in a player's inventory?

I have a script that checks if you have more than one tomato picked up in your inventory, then tells you that you already have one if you already have one, with a gui controlled by a module script "wait"

but i dont know how to check how many of a tool is inside your inventory

cd.MouseClick:Connect(function(humanoid)

if db then
		db = false
	local inv = humanoid.Backpack 
	local tool = game.ServerStorage["Tomato"]
	tool:Clone().Parent = inv
		wait(2)
		if humanoid.Backpack.Tomato > 0 then --i dont know how to check 
			waitgui.enableAndDisable() --enableAndDisable is a function inside the module
			db = true
                end
          end
end)