Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If a monster(s) you control returns to your hand by an opponent's card effect: Return as many monsters on the field to the hand as possible, then each player Special Summons monsters from their hand, in face-down Defense Position, equal to the number of Monster Cards that were returned to their hand.
--大騒動
--Major Riot
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_TOHAND+CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_TO_HAND)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
end
function s.confilter(c,tp)
	return c:IsControler(tp) and c:IsPreviousLocation(LOCATION_MZONE)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return rp~=tp and eg:IsExists(s.confilter,1,nil,tp)
end
function s.thfilter(c,tp)
	return c:IsLocation(LOCATION_HAND) and c:IsControler(tp)
end
function s.spfilter(c,e,tp)
	return c:GetLevel()<=4 and c:IsSummonableCard() and c:IsCanBeSpecialSummoned(e,0,tp,false,false)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(Card.IsAbleToHand,tp,LOCATION_MZONE,LOCATION_MZONE,1,nil) end
	local g=Duel.GetMatchingGroup(Card.IsAbleToHand,tp,LOCATION_MZONE,LOCATION_MZONE,nil)
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,g,#g,0,0)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(Card.IsAbleToHand,tp,LOCATION_MZONE,LOCATION_MZONE,nil)
	if #g==0 then return end
	Duel.SendtoHand(g,nil,REASON_EFFECT)
	Duel.BreakEffect()
	local og=Duel.GetOperatedGroup()
	local ct1=og:FilterCount(s.thfilter,nil,tp)
	local ct2=og:FilterCount(s.thfilter,nil,1-tp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g1=Duel.SelectMatchingCard(tp,s.spfilter,tp,LOCATION_HAND,0,ct1,ct1,nil,e,tp)
	if #g1>0 then
		local tc=g1:GetFirst()
		for tc in aux.Next(g1) do
			Duel.SpecialSummonStep(tc,0,tp,tp,false,false,POS_FACEDOWN_DEFENSE)
		end
	end
	Duel.Hint(HINT_SELECTMSG,1-tp,HINTMSG_SPSUMMON)
	local g2=Duel.SelectMatchingCard(1-tp,s.spfilter,1-tp,LOCATION_HAND,0,ct2,ct2,nil,e,1-tp)
	if #g2>0 then
		local tc=g2:GetFirst()
		for tc in aux.Next(g2) do
			Duel.SpecialSummonStep(tc,0,1-tp,1-tp,false,false,POS_FACEDOWN_DEFENSE)
		end
	end
	Duel.SpecialSummonComplete()
end