N=int(input())
A=list(map(int,input().split()))
B=list(map(int,input().split()))
A.sort()
B.sort()

left=[0]*N
for i in range(N-1):
    left[i+1]=left[i]+abs(A[i]-B[i])

right=[0]*N
for i in range(N-1):
    right[i+1]=right[i]+abs(A[~i]-B[~i])

best=10**18
ans=set()
for i in range(N):
    tmp=left[i]+right[N-1-i]
    if tmp<best:
        ans=set([A[i]])
        best=tmp
    elif tmp==best:
        ans.add(A[i])

print(len(ans))
print(*sorted(list(ans)))