import sys, time, random
from collections import deque, Counter, defaultdict
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

n, k = mi()

a = list(Counter(li()).values())

ans = 0

a.sort(reverse=True)

for v in a:
    ans += 1
    k -= v
    if k <= 0:
        break
print(ans)