#include"bits/stdc++.h"

using namespace std;

const int N = 1e6 + 10;

int n, w;

void solve() {
	cin >> n >> w;
	vector<int> a(14, 0);
	for(int i = 1; i <= n; i++) {
		int x;
		cin >> x;
		a[x - 1]++;
	}
	vector<int> dp((1 << 13) + 10, 20);
	dp[0] = 0;
	for(int i = 0; i < (1 << 13); i++) {
		vector<int> kk;
		int cnt = 0;
		for(int j = 0; j < 13; j++) {
			if(!(i & (1 << j))) {
				kk.push_back(j), cnt++;
			}
		}
		for(int j = 1; j < (1 << cnt); j++) {
			int sum = 0, to = i;
			for(int k = 0; k < cnt; k++)  {
				if(j & (1 << k)) sum += a[kk[k]], to ^= (1 << kk[k]); 
			}
			if(sum <= w) dp[to] = min(dp[i] + 1, dp[to]);
		}
		//cout << dp[i] << "\n";
	}
	cout << dp[(1 << 13) - 1] << "\n";
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	int t = 1;
	//cin >> t;
	while(t--) solve();
	return 0;
}