#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
#define all(x) (x).begin(),(x).end()

template<typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    for (int i = 0; i < int(v.size()); i++) cout << v[i] << (i + 1 == int(v.size()) ? "" : " ");
    return os;
}

#ifdef LOCAL
#define debug(x) cerr << #x << " = " << "(L" << __LINE__ << ")" << x << endl;
#else
#define debug(x)
#endif

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, w;
    cin >> n >> w;
    vector<int> a(13);
    for (int i = 0; i < n; i++) {
        int b;
        cin >> b;
        a[b - 1]++;
    }
    int ans = 0;
    for (int i = 0; i < 13; i++) {
        ans += a[i] / w;
        a[i] %= w;
    }
    vector<int> f(1 << 13);
    for (int i = 0; i < (1 << 13); i++) {
        for (int j = 0; j < 13; j++) {
            if (i & (1 << j)) {
                f[i] += a[j];
            }
        }
    }
    vector<int> dp(1 << 13, (int) 1e9);
    dp[0] = 0;
    for (int mask = 1; mask < (1 << 13); mask++) {
        int nmask = mask;
        while (nmask >= 0) {
            if (f[mask ^ nmask] <= w) {
                dp[mask] = min(dp[mask], dp[nmask] + 1);
            }
            if (nmask == 0) {
                break;
            }
            nmask = (nmask - 1) & mask;
        }
    }
    ans += dp.back();
    cout << ans << '\n';
    return 0;
}