#include <bits/stdc++.h>
using namespace std;

const int MAXNUM = 13;
const int MAXPOW = 8192;

int main() {
  int n, W;
  cin >> n >> W;

  int a[MAXNUM];
  for (int i = 0; i < n; i++) {
    int val;
    cin >> val;
    a[--val]++;
  }

  vector<int> viable;
  // dp[bitmask] = min days to learn all words of lengths described by bitmask
  int dp[MAXPOW];
  for (int i = 0; i < MAXPOW; i++) {
    dp[i] = MAXNUM;
    
    int val = i;
    int sum = 0;
    for (int j = 0; j < 13; j++) {
      if (val % 2 == 1) {
	sum += a[j];
      }
      val /= 2;
    }
    if (sum <= W) {
      viable.push_back(i);
    }
  }

  dp[0] = 0;
  for (int i = 0; i < MAXPOW; i++) {
    for (int bitmask : viable) {
      if ((i & bitmask) == 0) {
	int or_mask = i | bitmask;
	dp[or_mask] = min(dp[or_mask], dp[i] + 1);
      }
    }
  }
  cout << dp[MAXPOW - 1] << endl;
}