Can someone figure out the problem of why this script wont run?

Can somebody fix this, as in finding the error, of why it wont run, and fixing it manually?

Maps = {"Wobbly Bridge","Tower Of Magic"}

Time_Per_Round = 60

HowLongMessageLasts = 5

HowLongVotingPeriodLasts = 15

MessageToBeStated = "Seconds Left: "

Option = 1

COLOR = 1

function Op1()

    m = Instance.new("Message", Workspace)

    m.Text = "Map Selected: ".. MAP .."!"

    wait(3)

    m:Destroy()

end

function Op2()

    m = Instance.new("Message", Workspace)

    m.Text = "".. MAP .."____ was picked!"

    wait(3)

    m:Destroy()

end

function Op3()

    m = Instance.new("Message", Workspace)

    m.Text = "You will be playing on the ".. MAP .." map"

    wait(3)

    m:Destroy()

end

function Op4()

    m = Instance.new("Message", Workspace)

    m.Text = ""

    wait(3)

    m:Destroy()

end

Players = game.Players:GetPlayers()

Ls = game.Lighting:GetChildren()

_G.MAPA = {"Wobbly Bridge"}

_G.MAPB = {"Tower Of Magic"}

_G.NothingCurrently = {}

Lasting = HowLongVotingPeriodLasts

while true do

    HowLongVotingPeriodLasts = Lasting

    if #Players > 1 then

        for o = 1,#Players do

            gui = game.Lighting.Vote:Clone()

            gui.Parent = Players[o].PlayerGui

        end

        repeat

            a = HowLongVotingPeriodLasts

            wait(1)

            m = Instance.new("Message", Workspace)

            m.Text = "Voting Time: "

            a = a - 1

            wait(1)        

        until a == 0

        m:Destroy()

        for i = 1,#Players do

            val = Players[i].Map.Value

            table.insert(_G[val], val)

        end

            mapn = math.max(#_G.MAPA, #_G.MAPB)

            if #_G.MAPA == mapn then

                for u = 1,#Ls do

                    if Ls[u]:FindFirstChild("A") ~= nil then

                        Pick = Ls[u]

                    end

                end

            end

        Mapp = Pick:Clone()

        Mapp.Parent = Workspace

        MAP = Mapp.Name

        if Option == 1 then

           Op1()

        elseif Option == 2 then

            Op2()

        elseif Option == 3 then

            Op3()

        elseif Option == 4 then

            Op4()

        else

            print("Invalid option")

        end

        for y = 1,#Players do

            if COLOR == 1 then

                Players[y].TeamColor = BrickColor.new("Really red")

                COLOR = 2

            elseif COLOR == 2 then

                Players[y].TeamColor = BrickColor.new("Really blue")

                COLOR = 1

            end

        end

    end

end