#pragma GCC optimize(3,"Ofast","inline")
#pragma GCC optimize(2)
#include <bits/stdc++.h>
#define ll int
#define mod 998244353
#define Ma 500005
#define G 3
#define N 13
#define pb push_back
#define L (1<<21)
using namespace std;
ll dp[1<<N],g[1<<N];
ll vis[1<<N];
ll a[1<<N];
ll n,m,k;
ll inf=1e9;

ll lowbit(ll x)
{
    return x&(-x);
}

void sol()
{
    cin>>n>>m;
    for (ll i=1;i<=n;i++)
    {
        ll x;
        cin>>x;
        x--;
        a[1<<x]++;
    }
    for (ll i=1;i<(1<<N);i++)
        g[i]=g[i-lowbit(i)]+a[lowbit(i)],dp[i]=inf;
    queue <ll> q;
    q.push(0);
    vis[0]=1;
    while (!q.empty())
    {
        ll p=q.front();
        q.pop();
        for (ll i=0;i<(1<<N);i++)
        {
            if (g[i]<=m)
            {
                ll ne=p|i;
                if (vis[ne])
                    continue;
                vis[ne]=1;
                dp[ne]=dp[p]+1;
                q.push(ne);
            }
        }
    }
    printf("%d\n",dp[(1<<N)-1]);
    return;
}

int	main(){
    ios::sync_with_stdio(0); cin.tie(0);
    int tt=1;
    while (tt--)
        sol();
    return 0;
}
/*
500000 500000

*/