from collections import Counter

n, m = map(int, input().split())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
dict = Counter(a)
r = [0] * m

for k, v in dict.items():
    r[k-1] = v

ans = 0
for i in range(m):
    c = r[i] - b[i]
    if c > 0:
        ans += c

print(ans)