def solution(n, lost, reserve):
answer = 0
delete_list = []
lost.sort()
reserve.sort()
for i in lost:
if i in reserve:
delete_list.append(i)
for i in delete_list:
lost.remove(i)
reserve.remove(i)
for i in reserve:
if i+1 in lost:
lost.remove(i+1)
elif i-1 in lost:
lost.remove(i-1)
total = len(lost)
answer= n - total
return answer