#include <iostream>
#include <vector>
#include <map>
using namespace std;
#define rep(i,n) for(int i = 0;i<n;i++)

int main()
{
    int n, k; cin>>n>>k;
    vector<int>a(n); 
    map<int,int>b; // kind -> count
    multimap<int,int>c; // count -> kind
    rep(i,n) cin>>a[i];
    rep(i,n) b[a[i]]++;
    for(auto it=b.begin();it!=b.end();it++){
        c.emplace(it->second,it->first);
    }
    int ans=0;
    int cnt=0;
    for(auto it=c.rbegin();it!=c.rend();it++){
        ans++;
        cnt+=it->first;
        if(cnt>=k) break;
    }
    cout << ans << endl;
    return 0;
}