#include<bits/stdc++.h>
#define il inline
using namespace std;
const int maxn=50010;
const int maxs=1<<13;
const int maxm=17;
il int read(){
	int x=0;
	char c=getchar();
	for(;!(c>='0'&&c<='9');c=getchar());
	for(;c>='0'&&c<='9';c=getchar())
		x=(x<<1)+(x<<3)+c-'0';
	return x;
}
int n,m,W;
int w[maxm];
int f[maxs];
int g[maxs];
int main(){
	n=read(),W=read();
	for(int i=1,x;i<=n;i++) 
		w[x=read()]++,m=max(m,x);
	int state=1<<m;
	for(int s=0;s<state;s++)
		for(int i=1;i<=m;i++)
			if((s>>i-1)&1) g[s]+=w[i];
	memset(f,127,sizeof(f)),f[0]=0;
	for(int s=0;s<state;s++)
		for(int t=s;t<state;t=(t+1)|s)
			if(g[t^s]<=W) f[t]=min(f[t],f[s]+1);
	printf("%d\n",f[state-1]);
	return 0;
}