#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using P = pair<int, int>;

int main() {
    int n, k;
    cin >> n >> k;
    
    vector<int> a(n);
    rep(i, n) cin >> a[i];
    rep(i, n) a[i]--;
    
    vector<int> cnt(n);
    rep(i, n) cnt[a[i]]++;
    
    map<int, int> mp; 
    set<int> s;
    rep(i, n) {
        if (s.count(a[i])) continue;
        mp[cnt[a[i]]]++;
        s.insert(a[i]);
    }
    
    vector<P> ps;
    for (auto [c, y] : mp) {
        ps.emplace_back(c, y);
    }
    
    sort(ps.rbegin(), ps.rend());
    
    int ans = 0;
    for (auto [c, y] : ps) {
        while (y) {
            ans++;
            int nc = c;
            k -= nc;
            if (k <= 0) {
                cout << ans << '\n';
                return 0;
            }
            y--;
        }
    }
    
    return 0;
}