#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


constexpr int INF = 1001001001;

int N, W;
vector<int> A;

int main() {
  for (; ~scanf("%d%d", &N, &W); ) {
    A.resize(N);
    for (int i = 0; i < N; ++i) {
      scanf("%d", &A[i]);
      --A[i];
    }
    
    const int lim = *max_element(A.begin(), A.end()) + 1;
    vector<int> freq(lim, 0);
    for (int i = 0; i < N; ++i) {
      ++freq[A[i]];
    }
    vector<int> cs(1 << lim, 0);
    for (int j = 0; j < lim; ++j) {
      for (int p = 0; p < 1 << j; ++p) {
        cs[p | 1 << j] = cs[p] + freq[j];
      }
    }
    vector<int> dp(1 << lim, INF);
    dp[0] = 0;
    for (int p = 1; p < 1 << lim; ++p) {
      for (int q = p; q; --q &= p) if (cs[q] <= W) {
        chmin(dp[p], dp[p - q] + 1);
      }
    }
    printf("%d\n", (int)dp.back());
  }
  return 0;
}