n,m = [int(x) for x in input().split()]
a = []
b = []
colors = {}
for i in range(n):
    x = int(input())
    if(x not in colors):
        colors[x] = 1
    else:
        colors[x] = 2
    a.append(int(x))
for i in range(m):
    x = int(input())
    if(x not in colors):
        colors[x] = 1
    else:
        colors[x] = 2
    b.append(int(x))
counter = 0
for i in colors:
    if(colors[i] == 2):
        counter += 1
answer = []
print(counter)
for i in colors:
    if(colors[i] == 2):
        answer.append(i)
answer.sort()
for i in range(counter):
    print(answer[i], end = " ")
print()
a.sort()
print(n - counter)
for i in range(n):
    if (colors[a[i]] == 1):
        print(a[i], end = " ")
print()
b.sort()
print(m - counter)
for i in range(m):
    if colors[b[i]] == 1:
        print(b[i], end = " ")