a=2.times.map{gets;gets.split.map(&:to_i).sort}
p [0,1].map{|e|c=a[e][0]
i=[0,0]
t=e^r=1
loop{i[t]+=1 until (f=i[t]>=a[t].size)||c<v=a[t][i[t]]
break if f
c=v
r+=1
t^=1
}
r}.max