from collections import Counter

N, M = [int(s) for s in input().split()]
A = [int(s) for s in input().split()]
B = [int(s) for s in input().split()]

cnt_a = Counter(A)
ans = 0

for i in range(M):
    ans += max(cnt_a[i + 1] - B[i], 0)

print(ans)