# coding: utf-8
# Your code here!

N,K=map(int,input().split())
A=list(map(int,input().split()))

log=[0]*N

for a in A:
    log[a-1]+=1

log.sort(reverse=True)

specie=0
for l in log:
    K-=l
    specie+=1
    if K<=0:
        break

print(specie)