#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int N, K, A, cnt=0;
    cin >> N >> K;
    map<int, int> mp;
    for (int i=0; i<N; i++){
        cin >> A;
        mp[A]++;
    }
    priority_queue<int> que;
    for (auto [x, y] : mp) que.push(y);
    while(K > 0 && !que.empty()){
        A = que.top();
        que.pop();
        cnt++;
        K -= A;
    }

    cout << cnt << endl;

    return 0;
}