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

left = [abs(A[i] - B[i]) for i in range(N-1)]
right = [abs(A[i+1] - B[i]) for i in range(N-1)]
leftS = [v:=0] + [v:=v+left[i] for i in range(N-1)]
rightS = ([v:=0] + [v:=v+right[i] for i in range(N-2,-1,-1)])[::-1]

MIN = min([leftS[i] + rightS[i] for i in range(N)])
ans = set()
for i in range(N):
    if(leftS[i] + rightS[i] == MIN):ans.add(A[i])
print(len(ans))
print(*sorted(ans))