Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn, you can flip this card into face-down Defense Position. When this card is flipped face-up, you can return monsters your opponent controls to their owners' hand up to the number of face-up "Frog" monsters you control, except "Frog the Jam".
--裏ガエル
--Flip Flop Frog
local s,id=GetID()
function s.initial_effect(c)
	--turn set
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_POSITION)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetRange(LOCATION_MZONE)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
	--damage
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_TOHAND)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e2:SetProperty(EFFECT_FLAG_DAMAGE_STEP)
	e2:SetCode(EVENT_FLIP)
	e2:SetTarget(s.rettg)
	e2:SetOperation(s.retop)
	c:RegisterEffect(e2)
end
s.listed_series={SET_FROG}
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	local c=e:GetHandler()
	if chk==0 then return c:IsCanTurnSet() and c:GetFlagEffect(id)==0 end
	c:RegisterFlagEffect(id,RESET_EVENT|(RESETS_STANDARD_PHASE_END&~RESET_TURN_SET),0,1)
	Duel.SetOperationInfo(0,CATEGORY_POSITION,c,1,0,0)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsRelateToEffect(e) and c:IsFaceup() then
		Duel.ChangePosition(c,POS_FACEDOWN_DEFENSE)
	end
end
function s.rettg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(aux.FaceupFilter(Card.IsSetCard,SET_FROG),tp,LOCATION_MZONE,0,1,nil)
		and Duel.IsExistingMatchingCard(Card.IsAbleToHand,tp,0,LOCATION_MZONE,1,nil) end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,nil,1,0,0)
end
function s.retop(e,tp,eg,ep,ev,re,r,rp)
	local ct=Duel.GetMatchingGroupCount(aux.FaceupFilter(Card.IsSetCard,SET_FROG),tp,LOCATION_MZONE,0,nil)
	if ct==0 then return end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_RTOHAND)
	local g=Duel.SelectMatchingCard(tp,Card.IsAbleToHand,tp,0,LOCATION_MZONE,1,ct,nil)
	Duel.HintSelection(g)
	Duel.SendtoHand(g,nil,REASON_EFFECT)
end