// Hallelujah, praise the one who set me free
// Hallelujah, death has lost its grip on me
// You have broken every chain, There's salvation in your name
// Jesus Christ, my living hope
#include <bits/stdc++.h> 
using namespace std;

#define REP(i, s, e) for (int i = (s); i < (e); i++)
#define RREP(i, s, e) for (int i = (s); i >= (e); i--)
template <class T>
inline bool mnto(T& a, T b) {return a > b ? a = b, 1 : 0;}
template <class T>
inline bool mxto(T& a, T b) {return a < b ? a = b, 1: 0;}

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
#define ALL(_a) _a.begin(), _a.end()
#define SZ(_a) (int) _a.size()
#define pb push_back
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ii> vii;
typedef vector<iii> viii;

#ifndef DEBUG
#define cerr if (0) cerr
#endif

const int INF = 1000000005;
const ll LINF = 1000000000000000005ll;
const int MAXN = 50005;
const int MAXM = 13;

int n, m, w;
int a[MAXN], b[MAXM];
vi gd;
int dp[1 << MAXM];
queue<int> qu;

int main() {
#ifndef DEBUG
    ios::sync_with_stdio(0), cin.tie(0);
#endif
    cin >> n >> w;
    REP (i, 0, n) {
        cin >> a[i];
        b[a[i] - 1]++;
    }
    REP (msk, 0, 1 << MAXM) {
        int sm = 0;
        REP (i, 0, MAXM) {
            if (msk >> i & 1) {
                sm += b[i];
            }
        }
        if (sm <= w) {
            gd.pb(msk);
        }
    }
    REP (i, 0, 1 << MAXM) {
        dp[i] = INF;
    }
    dp[0] = 0;
    qu.push(0);
    while (!qu.empty()) {
        int msk = qu.front(); qu.pop();
        for (int v : gd) {
            int nmsk = msk | v;
            if (mnto(dp[nmsk], dp[msk] + 1)) {
                qu.push(nmsk);
            }
        }
    }
    cout << dp[(1 << MAXM) - 1] << '\n';
    return 0;
}