from collections import Counter

n, k = map(int, input().split())
A = list(map(int, input().split()))

counter = Counter(A)
C = [cnt for cnt in counter.values()]
C.sort(reverse=True)
ans = 0
res = 0
for i in range(n):
    res += C[i]
    ans += 1
    if res >= k:
        break
print(ans)