Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
2 "HERO" Normal Monsters Must be Fusion Summoned. Gains ATK/DEF equal to the combined original Levels of the materials used for its Fusion Summon x 300. When this card destroys an opponent's monster by battle: You can Tribute this card; Special Summon 1 "Elemental HERO" Fusion Monster from your Extra Deck, ignoring its Summoning conditions, but it cannot attack monsters with an equal or lower Level than it.
--E・HERO グランドマン
--Elemental HERO Grandmerge
--Scripted by AlphaKretin
local s,id=GetID()
function s.initial_effect(c)
	--fusion material
	c:EnableReviveLimit()
	Fusion.AddProcMixN(c,true,true,s.ffilter,2)
	--spsummon condition
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e1:SetCode(EFFECT_SPSUMMON_CONDITION)
	e1:SetValue(aux.fuslimit)
	c:RegisterEffect(e1)
	--atk
	local e0=Effect.CreateEffect(c)
	e0:SetType(EFFECT_TYPE_SINGLE)
	e0:SetCode(EFFECT_MATERIAL_CHECK)
	e0:SetValue(s.valcheck)
	c:RegisterEffect(e0)
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_CONTINUOUS)
	e2:SetCode(EVENT_SPSUMMON_SUCCESS)
	e2:SetCondition(s.atkcon)
	e2:SetOperation(s.atkop)
	e2:SetLabelObject(e0)
	c:RegisterEffect(e2)
	--special summon
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,0))
	e3:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e3:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e3:SetCode(EVENT_BATTLE_DESTROYING)
	e3:SetCondition(s.spcon)
	e3:SetCost(Cost.SelfTribute)
	e3:SetTarget(s.sptg)
	e3:SetOperation(s.spop)
	c:RegisterEffect(e3)
end
s.listed_series={SET_ELEMENTAL_HERO}
s.material_setcode={SET_HERO}
function s.ffilter(c,fc,sumtype,tp)
	return c:IsType(TYPE_NORMAL,fc,sumtype,tp) and c:IsSetCard(SET_HERO,fc,sumtype,tp)
end
function s.valcheck(e,c)
	local g=c:GetMaterial()
	local atk=0
	for tc in aux.Next(g) do
		atk=atk+tc:GetOriginalLevel()
	end
	e:SetLabel(atk)
end
function s.atkcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():IsFusionSummoned()
end
function s.atkop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local atk=e:GetLabelObject():GetLabel()*300
	if atk>0 then
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_UPDATE_ATTACK)
		e1:SetValue(atk)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD_DISABLE)
		c:RegisterEffect(e1)
		local e2=e1:Clone()
		e2:SetCode(EFFECT_UPDATE_DEFENSE)
		c:RegisterEffect(e2)
	end
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local bc=c:GetBattleTarget()
	return c:IsRelateToBattle() and bc and bc:IsMonster()
end
function s.spfilter(c,e,tp)
	return c:IsType(TYPE_FUSION) and c:IsSetCard(SET_ELEMENTAL_HERO) and Duel.GetLocationCountFromEx(tp,tp,e:GetHandler(),c)>0 and c:IsCanBeSpecialSummoned(e,0,tp,true,false)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_EXTRA,0,1,nil,e,tp) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_EXTRA)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,s.spfilter,tp,LOCATION_EXTRA,0,1,1,nil,e,tp)
	local tc=g:GetFirst()
	local c=e:GetHandler()
	if tc and Duel.SpecialSummonStep(tc,0,tp,tp,true,false,POS_FACEUP) then
		--atklimit
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_CANNOT_SELECT_BATTLE_TARGET)
		e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_IGNORE_IMMUNE)
		e1:SetValue(s.bttg)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD)
		tc:RegisterEffect(e1,true)
	end
	Duel.SpecialSummonComplete()
end
function s.bttg(e,c)
	return c:IsFaceup() and c:IsLevelBelow(e:GetHandler():GetLevel())
end