import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
#sys.setrecursionlimit(10**9)
#n = int(input())
n,k = map(int,input().split())
alist = list(map(int,input().split()))
#hen = collections.defaultdict(list)
#s = input()
#
#for i in range(n):
#    alist.append(list(map(int,input().split())))
#    u,v = map(int,input().split())
#    hen[u].append(v)
#    hen[v].append(u)
#dp = [[0]*n for i in range(m)]
c = collections.Counter(alist)
h = []
for i in set(alist):
	heapq.heappush(h,-c[i])
ans = 0
temp = 0
while temp < k:
	ans += 1
	temp -= heapq.heappop(h)
print(ans)