#include <bits/stdc++.h>
using namespace std;
const int N=5e4+100;
int n,W;
int a[N];
int cnt[13];
int scnt[1<<13];
int f[1<<13];
int main(){
	scanf("%d%d",&n,&W);
	for(int i=1;i<=n;i++){
		scanf("%d",&a[i]);
		cnt[a[i]-1]++;
	}
	memset(f,0x3f,sizeof(f));
	f[0]=0;
	for(int i=1;i<(1<<13);i++){
		int sp=0;
		while(((i>>sp)&1)==0) sp++;
		scnt[i]=cnt[sp]+scnt[i^(1<<sp)];
		for(int j=i;j;j=(j-1)&i) if(scnt[j]<=W){
			f[i]=min(f[i],f[i^j]+1);
		}
	}
	cout<<f[(1<<13)-1];
}