//code by Emissary
#include<bits/stdc++.h>

#define fi first
#define se second
#define vc vector
#define db double
#define ll long long
#define mk make_pair
#define pb push_back
#define PI pair<int,int>
#define ull unsigned long long
#define err cerr << "   -_-   " << endl
#define debug cerr << " ------------------- " << endl

#define input(x) freopen(#x".in","r",stdin)
#define output(x) freopen(#x".out","w",stdout)

#define NO puts("No")
#define YES puts("Yes")

//#define int long long

using namespace std;

namespace IO{
	inline int read(){
		int X=0, W=0; char ch=getchar();
		while(!isdigit(ch)) W|=ch=='-', ch=getchar();
		while(isdigit(ch)) X=(X<<1)+(X<<3)+(ch^48), ch=getchar();
		return W?-X:X;
	}
	inline void write(int x){
		if(x<0) x=-x, putchar('-');
		if(x>9) write(x/10);
		putchar(x%10+'0');
	}
	inline void sprint(int x){write(x), putchar(32);}
	inline void eprint(int x){write(x), putchar(10);}
}using namespace IO;

const int MAXN = 5e5+5;
const int mod = 998244353;
//const int mod = 1e9+7;

int n, w;
int cnt[MAXN];

int f[1 << 20];

signed main(){
	n=read(), w=read();
	for(int i=1;i<=n;++i) cnt[read()]++;
	memset(f,127/3,sizeof f); f[0]=0;
	for(int i=0;i<1<<13;++i){
		int t=(1<<13)-1;
		int u=t^i;
		for(int o=u;o;o=(o-1)&u){
			int ss=0;
			for(int j=1;j<=13;++j){
				if((o>>(j-1))&1) ss+=cnt[j];
			}
			if(ss<=w) f[i|o]=min(f[i|o],f[i]+1);
		}
	}
	cout << f[(1<<13)-1];
	return 0;
}