Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If this card is Normal Summoned: Place 3 counters on it. Cannot be destroyed by battle. At the end of the Damage Step, if this card battled: Remove 1 counter from this card. If you cannot, destroy it.
--巨大戦艦 ビッグ・コア
--B.E.S. Big Core
local s,id=GetID()
function s.initial_effect(c)
	c:EnableCounterPermit(0x1f)
	--summon success
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_COUNTER)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e1:SetCode(EVENT_SUMMON_SUCCESS)
	e1:SetTarget(s.addct)
	e1:SetOperation(s.addc)
	c:RegisterEffect(e1)
	--battle indestructable
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetCode(EFFECT_INDESTRUCTABLE_BATTLE)
	e2:SetValue(1)
	c:RegisterEffect(e2)
	--remove counter
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,1))
	e3:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e3:SetCode(EVENT_DAMAGE_STEP_END)
	e3:SetCondition(s.rctcon)
	e3:SetOperation(s.rctop)
	c:RegisterEffect(e3)
	--destroy
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,2))
	e4:SetCategory(CATEGORY_DESTROY)
	e4:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e4:SetCode(EVENT_DAMAGE_STEP_END)
	e4:SetCondition(s.descon)
	e4:SetTarget(s.destg)
	e4:SetOperation(s.desop)
	c:RegisterEffect(e4)
end
function s.addct(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	Duel.SetOperationInfo(0,CATEGORY_COUNTER,nil,3,0,0x1f)
end
function s.addc(e,tp,eg,ep,ev,re,r,rp)
	if e:GetHandler():IsRelateToEffect(e) then
		e:GetHandler():AddCounter(0x1f,3)
	end
end
function s.rctcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():GetCounter(0x1f)~=0
end
function s.rctop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsFaceup() and c:IsRelateToEffect(e) then
		c:RemoveCounter(tp,0x1f,1,REASON_EFFECT)
	end
end
function s.descon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():GetCounter(0x1f)==0
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chk==0 then return true end
	Duel.SetOperationInfo(0,CATEGORY_DESTROY,e:GetHandler(),1,0,0)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsFaceup() and c:IsRelateToEffect(e) then
		Duel.Destroy(c,REASON_EFFECT)
	end
end