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

#define all(x) begin(x), end(x)
#ifdef CKISEKI
#define safe cerr << __PRETTY_FUNCTION__ << " line " << __LINE__ << " safe\n"
#define debug(a...) debug_(#a, a)
#define orange(a...) orange_(#a, a)
void debug_(const char *s, auto ...a) {
  cerr << "\e[1;32m(" << s << ") = (";
  int f = 0;
  (..., (cerr << (f++ ? ", " : "") << a));
  cerr << ")\e[0m\n";
}
void orange_(const char *s, auto L, auto R) {
  cerr << "\e[1;33m[ " << s << " ] = [ ";
  for (int f = 0; L != R; ++f)
    cerr << (f++ ? ", " : "") << *L++;
  cerr << " ]\e[0m\n";
}
#else
#define safe ((void)0)
#define debug safe
#define orange safe
#endif

const int C = 13;
int sum[1 << C], dp[1 << C];
int cnt[C] = {};

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, W;
  cin >> n >> W;
  vector<int> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    ++cnt[a[i] - 1];
  }

  for (int s = 0; s < (1 << C); s++) {
    for (int i = 0; i < C; i++)
      if (s >> i & 1)
        sum[s] += cnt[i];
  }

  memset(dp, 0x3f, sizeof(dp));
  dp[0] = 0;
  for (int s = 0; s < (1 << C); s++) {
    for (int m = s; m; m = (m - 1) & s) {
      if (sum[m] <= W)
        dp[s] = min(dp[s], dp[s ^ m] + 1);
    }
  }
  cout << dp[(1 << C) - 1] << '\n';

  return 0;
}