how to make a shift to sprint roblox

local UIS = game:GetService("UserInputService")
local Player = game.Players.LocalPlayer
local Character = script.Parent -- Put a LocalScript into StartPlayer > StarterCharacterScript
local Humanoid = Character:WaitForChild("Humanoid")

UIS.InputBegan:Connect(function(Key)
	if Key.KeyCode == Enum.KeyCode.LeftShift or Enum.KeyCode.RightShift then
    	local Running = true
        Humanoid.WalkSpeed = 32
	end
end

UIS.InputEnded:Connect(function(Key)
	if Key.KeyCode == Enum.KeyCode.LeftShift or Enum.KeyCode.RightShift then
    	local Running = false
        Humanoid.WalkSpeed = 16
	end
end