from collections import Counter
N, K = map(int, input().split())
A = list(map(int, input().split()))

items = [k for k in Counter(A).values()]

items.sort(reverse = True)
ans = 0
cnt = 0
i = 0
while cnt < K:
  ans += 1
  cnt += items[i]
  i += 1
print(ans)