Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If your opponent controls a monster and you control no monsters, you can Normal Summon this card without Tributing, but its original ATK becomes 1300.
--地獄大百足
--Hundred-Footed Horror
local s,id=GetID()
function s.initial_effect(c)
	--summon with no tribute
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_SUMMON_PROC)
	e1:SetCondition(s.ntcon)
	e1:SetOperation(s.ntop)
	c:RegisterEffect(e1)
end
function s.ntcon(e,c,minc)
	if c==nil then return true end
	local tp=c:GetControler()
	return minc==0 and Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.GetFieldGroupCount(tp,0,LOCATION_MZONE)>0
		and Duel.GetFieldGroupCount(tp,LOCATION_MZONE,0)==0
end
function s.ntop(e,tp,eg,ep,ev,re,r,rp,c)
	--change base attack
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetProperty(EFFECT_FLAG_SINGLE_RANGE)
	e1:SetRange(LOCATION_MZONE)
	e1:SetReset(RESET_EVENT|RESETS_STANDARD_DISABLE&~RESET_TOFIELD)
	e1:SetCode(EFFECT_SET_BASE_ATTACK)
	e1:SetValue(1300)
	c:RegisterEffect(e1)
end