import sys
sys.stdin = open('input.txt')
input = sys.stdin.readline
n, m = map(int, input().split())
a = set(map(int, input().split()))
b = set(map(int, input().split()))
print(len(a | b) - len(a & b))
# print(len(a - b) + len(b - a))
import sys
sys.stdin = open('input.txt')
input = sys.stdin.readline
n, m = map(int, input().split())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
p1 = 0
p2 = 0
result = list()
while p1 < n and p2 < m:
if a[p1] <= b[p2]:
result.append(a[p1])
p1 += 1
else:
result.append(b[p2])
p2 += 1
if p1 < n:
result += a[p1:]
else:
result += b[p2:]
print(*result)
하루를 마치고