I,R=input,range
def J():
	return map(int,I().split())
N,K=J()
A=list(J())
B=[0]*(N+1)
for a in A:B[a]+=1
a=0
for b in sorted(B,reverse=True):
	a+=1
	if K<b:print(a).exit(0)
	K-=b