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)