Why doesnt my script work when i press W twice?

The point is to make a player run when u press W twice, and stop when u let go of the keys.

local Trcanje = Instance.new('Animation') local Player = game.Players.LocalPlayer local Character = Player.Character local TickJeste = tick() Trcanje.AnimationId = 'rbxassetid://4766569612' PlayTrcanje = Character.Humanoid:LoadAnimation(Trcanje)

game:GetService("UserInputService").InputBegan:connect(function(input,gameprocesed) if input.KeyCode == Enum.KeyCode.Z then for i = 1,16 do local TickDa = tick() local TimePassed = TickDa - TickJeste wait(0.3) if TimePassed <= 1 then wait() game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed + 1.5 PlayTrcanje:Play() end end end end)

game:GetService("UserInputService").InputEnded:connect(function(input,gameprocesed) if input.KeyCode == Enum.KeyCode.Z then for i = 1,16 do local TimePassed = TickJeste wait(0.3) if TimePassed <= 1 then wait() game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed - 1.5 PlayTrcanje:Stop() end end end end)

game.Players.LocalPlayer.Character:WaitForChild("Humanoid").Died:connect(function() game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16 script.Disabled = true end)

local Trcanje = Instance.new('Animation') 
local Player = game.Players.LocalPlayer
local Character = Player.Character
local TickJeste = tick()
 Trcanje.AnimationId = 'rbxassetid://4766569612'
 PlayTrcanje = Character.Humanoid:LoadAnimation(Trcanje)

game:GetService("UserInputService").InputBegan:connect(function(input,gameprocesed)
 if input.KeyCode == Enum.KeyCode.Z then
  for i = 1,16 do
local TickDa = tick()
local TimePassed = TickDa - TickJeste
if TimePassed <= 1 then
  wait()
   game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed + 1.5
	PlayTrcanje:Play()
   end
  end
 end
end)


game:GetService("UserInputService").InputEnded:connect(function(input,gameprocesed)
 if input.KeyCode == Enum.KeyCode.Z then
  for i = 1,16 do
	local TimePassed = TickJeste
	if TimePassed <= 1 then
  wait()
   game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed = game.Players.LocalPlayer.Character:WaitForChild("Humanoid").WalkSpeed - 1.5
	PlayTrcanje:Stop()
   end
  end
 end
end)

game.Players.LocalPlayer.Character:WaitForChild("Humanoid").Died:connect(function()
 game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
 script.Disabled = true
end)