# coding: utf-8
#yuki_110

def solve(l1,l2):
 res=0
 i=21
 F=False
 while i>0:
  if l1[i] and not F:
   res+=1
   F=True
  elif l2[i] and F:
   res+=1
   F=False
  i-=1
 return res
 
 
nw=int(raw_input())
lmw=list(map(int, raw_input().split())) 
nb=int(raw_input())
lmb=list(map(int, raw_input().split())) 

w=list(set(lmw))
b=list(set(lmb))

w.sort()
w.reverse()
b.sort()
b.reverse()

lw=[0 for i in xrange(22)]
lb=[0 for i in xrange(22)]

for i in xrange(len(w)):
 lw[w[i]]=1
for i in xrange(len(b)):
 lb[b[i]]=1
  
res=max(solve(lw,lb),solve(lb,lw))
print res