N,K=map(int,input().split())
A=list(map(int,input().split()))
CardDict={}
for i in range(N):
    if A[i] in CardDict:
        CardDict[A[i]]+=1
    else:
        CardDict[A[i]]=1

Asorted=list(CardDict.values())
Asorted.sort(reverse=True)
count=0
for i in range(len(Asorted)):
    if K-Asorted[i]>=0:
        K-=Asorted[i]
        count+=1

print(count)