#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001

int main(){
	
	int n,k;
	cin>>n>>k;
	map<int,int> mp;
	rep(i,n){
		int a;
		cin>>a;
		mp[a]++;
	}
	
	vector<int> c(n+5);
	for(auto a:mp){
		c[a.second]++;
	}
	int ans = 0;
	for(int i=n;i>=0;i--){
		while(c[i]!=0&&k>0){
			k -= i;
			c[i]--;
			ans++;
		}
	}
	cout<<ans<<endl;
	
	return 0;
}