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

d = dict()
for b in a:
	if b in d:
		d[b] += 1
	else:
		d[b] = 1
l = sorted(d.values())
ans = 0
now = 0
while now < K:
	ans += 1
	now += l.pop()
print(ans)