2 scripts are almost the same thing, but why doesn't the first one work?

I tried to make a local script about UserInputService, my first script is:

local player = game.Players.LocalPlayer
local UIS = game:GetService("UserInputService")
mouse = player:GetMouse()
UIS.InputBegan:Connect(function(input)
    if input.UserInputType == Enum.UserInputType.Keyboard then
        print("you're pressing down a key")
    end
end)
UIS.InputEnded:Connect(function(input)
    if input.UserInputType == Enum.UserInputType.KeyBoard  then
        print("you stopped pressing a key")
    end

end)

but when i pressed play, i got an error: Keyboard is not a valid EnumItem

after that, i made another script:

local player = game.Players.LocalPlayer
local UIS = game:GetService("UserInputService")
mouse = player:GetMouse()
UIS.InputBegan:Connect(function(input)
    if input.UserInputType == Enum.UserInputType.MouseButton1 then
        print("you're pressing down a key")
    end
end)
UIS.InputEnded:Connect(function(input)
    if input.UserInputType == Enum.UserInputType.MouseButton1 then
        print("you stopped pressing a key")
    end

end)

I changed Keyboard to MouseButton1 and it works perfectly fine What is the problem here?