import sys
sys.setrecursionlimit(5*10**5)
input = sys.stdin.readline
from collections import defaultdict, deque, Counter
from heapq import heappop, heappush
from bisect import bisect_left, bisect_right
from math import gcd
n,k = map(int,input().split())
a = list(map(int,input().split()))

d = defaultdict(int)
for i in range(n):
    d[a[i]] += 1

v = list(d.values())
ans = 0
v.sort()
while k > 0:
    ans += 1
    k -=  v.pop()

print(ans)