from collections import Counter


N, K = map(int, input().split())
A = list(map(int, input().split()))

cnt = Counter(A)
lis = [cnt[i] for i in cnt]

lis.sort(reverse=True)

ans = 0
idx = 0
while 0 < K:
	ans += 1
	K -= lis[idx]
	idx += 1
print(ans)