N=int(input())
A=list(map(int,input().split()))
B=list(map(int,input().split()))
A.sort()
B.sort()
L=[0]
R=[0]
fuman=0
for i in range(N-1):
    fuman+=abs(A[i]-B[i])
    L.append(fuman)
fuman=0
for i in range(-1,-N,-1):
    fuman+=abs(A[i]-B[i])
    R.append(fuman)
R.reverse()
ans=10**9
#print(L)
#print(R)
#手元に残すハチマキを全探索
for i in range(N):
    ans=min(ans,L[i]+R[i])
l=set()
for i in range(N):
    if L[i]+R[i]==ans:
        l.add(A[i])
print(len(l))
print(*list(sorted(list(l))))