using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
using System.Threading;
using System.Runtime.CompilerServices;
using System.Diagnostics;
static class Program{
	const long inf=long.MaxValue>>1;
	const int mod=(int)1e9+7;
	static Sc sc=new Sc();
	static void Main(){
		Pt pt=new Pt(Solve);
		pt.Sm();
	}
	static void Solve(Pt pt) {
		var (n,m)=sc.Tp2<int>();
		var a=sc.Ia2;
		var bs=new Bitset[n+1];
		bs[0]=new Bitset(m+1,1);
		for(int i = 1;i <= n;i++) {
			bs[i]=new Bitset(bs[i-1]);
			bs[i]|=bs[i]<<a[i];
		}
		if(bs[n][m]==0) {
			pt.Wl(-1);
			return;
		}
		var bsr=new Bitset(m+1,1);
		int ans=0;
		for(int i = n;i > 0;i--) {
			var bo=true;
			for(int j = 0;j <= m;j++) {
				if((bs[i-1][j]&bsr[m-j])==1) {
					bo=false;
					break;
				}
			}
			if(bo) {ans++;}
			bsr|=bsr<<a[i];
		}
		pt.Wl(ans);
	}
}
public class Bitset{
	public int n,l;
	public ulong[] he;
	public Bitset(int n){
		this.n=n;
		l=(n>>6)+1;
		he=new ulong[l];
	}
	public Bitset(int n,long a){
		this.n=n;
		l=(n>>6)+1;
		he=new ulong[l];
		he[0]=(ulong)a;
	}
	public Bitset(int n,bool b){
		this.n=n;
		l=(n>>6)+1;
		he=new ulong[l];
		int y=n%64;
		if(y==0){for(int i = 0;i<l;i++) {he[i]=ulong.MaxValue;}}
		else{
			for(int i = 0;i<l-1;i++) {he[i]=ulong.MaxValue;}
			he[l-1]=(1UL<<y)-1;
		}
	}
	public Bitset(Bitset b){
		n=b.n;
		l=b.l;
		he=new ulong[l];
		for(int i = 0;i<l;i++) {he[i]=b.he[i];}
	}
	public int this[int i]{
		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		set{he[i>>6]=(he[i>>6]&(ulong.MaxValue^(1UL<<i)))|((ulong)value<<i);}
		get{return (int)((he[i>>6]>>i)&1);}
	}
	public static Bitset operator&(Bitset a,Bitset b){
		Bitset c=new Bitset(a.n);
		int d=Math.Min(a.l,b.l);
		for(int i=0;i<d;i++){c.he[i]=a.he[i]&b.he[i];}
		return c;
	}
	public static Bitset operator|(Bitset a,Bitset b){
		Bitset c;
		if(a.l<b.l){c=a;a=b;b=c;}
		c=new Bitset(a.n);
		int i=0;
		for(;i<b.l;i++){c.he[i]=a.he[i]|b.he[i];}
		for(;i<a.l;i++){c.he[i]=a.he[i];}
		return c;
	}
	public static Bitset operator^(Bitset a,Bitset b){
		Bitset c;
		if(a.l<b.l){c=a;a=b;b=c;}
		c=new Bitset(a.n);
		int i=0;
		for(;i<b.l;i++){c.he[i]=a.he[i]^b.he[i];}
		for(;i<a.l;i++){c.he[i]=a.he[i];}
		return c;
	}
	public static Bitset operator<<(Bitset a,int b){
		Bitset c=new Bitset(a.n);
		if(b>a.l<<6){return c;}
		int d=(b+63)>>6;
		if(b%64==0){for(int i=a.l-1;i>=d;i--){c.he[i]=a.he[i-d];}}
		else{
			for(int i=a.l-1;i>=d;i--){c.he[i]=(a.he[i-d+1]<<b)|(a.he[i-d]>>(64-b));}
			c.he[d-1]=a.he[0]<<b;
		}
		return c;
	}
	public static Bitset operator>>(Bitset a,int b){
		Bitset c=new Bitset(a.n);
		if(b>a.l<<6){return c;}
		int d=(b+63)>>6;
		if(b%64==0){for(int i=0;i+d<c.l;i++){c.he[i]=a.he[i+d];}}
		else{
			for(int i=0;i+d<c.l;i++){c.he[i]=(a.he[i+d-1]>>b)|(a.he[i+d]<<(64-b));}
			c.he[c.l-d]=a.he[c.l-1]>>b;
		}
		return c;
	}
	public static bool operator==(Bitset a,Bitset b){
		int mx=Max(a.l,b.l),mn=Min(a.l,b.l);
		for(int i=0;i<mn;i++){if(a.he[i]!=b.he[i]){return false;}}
		if(a.l>b.l){for(int i=mn;i<mx;i++){if(a.he[i]!=0){return false;}}}
		else{for(int i=mn;i<mx;i++){if(b.he[i]!=0){return false;}}}
		return true;
	}
	public static bool operator!=(Bitset a,Bitset b){
		int mx=Max(a.l,b.l),mn=Min(a.l,b.l);
		for(int i=0;i<mn;i++){if(a.he[i]!=b.he[i]){return true;}}
		if(a.l>b.l){for(int i=mn;i<mx;i++){if(a.he[i]!=0){return true;}}}
		else{for(int i=mn;i<mx;i++){if(b.he[i]!=0){return true;}}}
		return false;
	}
	public override bool Equals(object obj){return false;}
	public override int GetHashCode(){return 0;}
	public int cnt{get{
		int p=0;
		for(int i=0;i<l;i++){
			var bits=he[i];
			bits=(bits&0x5555555555555555)+(bits>>1&0x5555555555555555);
			bits=(bits&0x3333333333333333)+(bits>>2&0x3333333333333333);
			bits=(bits&0x0f0f0f0f0f0f0f0f)+(bits>>4&0x0f0f0f0f0f0f0f0f);
			bits=(bits&0x00ff00ff00ff00ff)+(bits>>8&0x00ff00ff00ff00ff);
			bits=(bits&0x0000ffff0000ffff)+(bits>>16&0x0000ffff0000ffff);
			p+=(int)((bits&0x00000000ffffffff)+(bits>>32&0x00000000ffffffff));
		}
		return p;
	}}
	public override string ToString(){
		string t="",s="";
		for(int i = 0;i<l-1;i++) {
			s=Convert.ToString((long)he[i],2);
			s=(64>s.Length?new string('0',64-s.Length):"")+s;
			t=s+t;
		}
		if(n%64!=0){
			s=Convert.ToString((long)he[l-1],2);
			s=((n%64)>s.Length?new string('0',(n%64)-s.Length):"")+s;
			return s+t;
		}
		return t;
	}
	public string Reverse{get{return string.Join("",ToString().Reverse());}}
	public void Ov0(int l,int r){
		if(l>>6==r>>6){he[r>>6]&=~((ulong.MaxValue<<(l-r-1))>>(63-r));}
		else{
			he[l>>6]&=~(ulong.MaxValue<<l);
			for(int i = (l>>6)+1;i<r>>6;i++) {he[i]=0;}
			he[r>>6]&=~(ulong.MaxValue>>(63-r));
		}
	}
	public void Ov1(int l,int r){
		if(l>>6==r>>6){he[r>>6]|=(ulong.MaxValue<<(l-r-1))>>(63-r);}
		else{
			he[l>>6]|=ulong.MaxValue<<l;
			for(int i = (l>>6)+1;i<r>>6;i++) {he[i]=ulong.MaxValue;}
			he[r>>6]|=ulong.MaxValue>>(63-r);
		}
	}
	public bool Fb(int l,int r){
		if(l>>6==r>>6){return (he[r>>6]&((ulong.MaxValue<<(l-r-1))>>(63-r)))!=0;}
		else{
			if((he[l>>6]&(ulong.MaxValue<<l))!=0){return true;}
			for(int i = (l>>6)+1;i<r>>6;i++) {if(he[i]!=0){return true;}}
			return (he[r>>6]&(ulong.MaxValue>>(63-r)))!=0;
		}
	}
}
public class Pt{
	private StringBuilder sb=new StringBuilder();
	public Pt(Action<Pt> f){f(this);}
	public void W(int s){sb.Append(s);}
	public void W(long s){sb.Append(s);}
	public void W(double s){sb.Append(s);}
	public void W(decimal s){sb.Append(s);}
	public void W(string s){sb.Append(s);}
	public void W(object s){sb.Append(s);}
	public void W(string f,int s){sb.Append(s.ToString(f));}
	public void W(string f,long s){sb.Append(s.ToString(f));}
	public void W(string f,double s){sb.Append(s.ToString(f));}
	public void W(string f,decimal s){sb.Append(s.ToString(f));}
	public void Wl(int s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(long s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(double s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(decimal s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(string s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(object s){sb.Append(s).Append(Environment.NewLine);}
	public void Wl(string f,int s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(string f,long s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(string f,double s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(string f,decimal s){sb.Append(s.ToString(f)).Append(Environment.NewLine);}
	public void Wl(int[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(long[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(double[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(string[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(object[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);}
	public void Wl(){sb.Append(Environment.NewLine);}
	public void Sm(){Console.Write(sb);}
	public static bool operator==(Pt a,Pt b){return a.sb.ToString()==b.sb.ToString();}
	public static bool operator!=(Pt a,Pt b){return a.sb.ToString()!=b.sb.ToString();}
	public override bool Equals(object obj){return false;}
	public override int GetHashCode(){return 0;}
}
public class Sc{
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected virtual string Rl(){return Console.ReadLine();}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected virtual string[] Sp(string st){return st.Split();}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	private T Ct<T>(string s){return (T)Convert.ChangeType(s,typeof(T));}
	public virtual int I{get{return int.Parse(Rl());}}
	public virtual long L{get{return long.Parse(Rl());}}
	public virtual double D{get{return double.Parse(Rl());}}
	public virtual string S{get{return Rl();}}
	public int[] Ia{get{return Array.ConvertAll(Sp(Rl()),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Sp(Rl()),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Sp(Rl()),double.Parse);}}
	public string[] Sa{get{return Sp(Rl());}}
	public object[] Oa{get{return Sp(Rl());}}
	public int[] Ia2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),int.Parse);}
	public int[] Ia3(int a){return Array.ConvertAll(Sp(Rl()+" "+a.ToString()),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),long.Parse);}
	public long[] La3(int a){return Array.ConvertAll(Sp(Rl()+" "+a.ToString()),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Sp(Rl()));}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Sp(Rl()));}return a;}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T) Tp2<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T) Tp3<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T) Tp4<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T,T) Tp5<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]),Ct<T>(s[4]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T,T,T) Tp6<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]),Ct<T>(s[4]),Ct<T>(s[5]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T1,T2) Tp2<T1,T2>(){var s=Sp(Rl());return (Ct<T1>(s[0]),Ct<T2>(s[1]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T1,T1,T2) Tp3<T1,T2>(){var s=Sp(Rl());return (Ct<T1>(s[0]),Ct<T1>(s[1]),Ct<T2>(s[2]));}
}
public class Scr:Sc{
	private List<string> li=new List<string>();
	private int l=0;
	private bool bo=false;
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected override string Rl(){
		if(bo){return li[l++%li.Count];}
		li.Add(Console.ReadLine());
		return li[li.Count-1];
	}
	public void Again(){bo=true;}
}
public class Sc2:Sc{
	private string[] sps=new string[]{" ","　","\t"};
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	protected override string[] Sp(string st){return st.Split(sps,StringSplitOptions.RemoveEmptyEntries);}
	public override int I{get{return int.Parse(Sp(Rl())[0]);}}
	public override long L{get{return long.Parse(Sp(Rl())[0]);}}
	public override double D{get{return double.Parse(Sp(Rl())[0]);}}
	public override string S{get{return Sp(Rl())[0];}}
}
public class Sct:Sc{
	private List<string> li=new List<string>();
	private int l=0;
	public void Add(int s){li.Add(s.ToString());}
	public void Add(long s){li.Add(s.ToString());}
	public void Add(double s){li.Add(s.ToString());}
	public void Add(string s){li.Add(s.ToString());}
	public void Add(object s){li.Add(s.ToString());}
	public void Add(int[] s){li.Add(string.Join(" ",s));}
	public void Add(long[] s){li.Add(string.Join(" ",s));}
	public void Add(double[] s){li.Add(string.Join(" ",s));}
	public void Add(string[] s){li.Add(string.Join(" ",s));}
	public void Add(object[] s){li.Add(string.Join(" ",s));}
	protected override string Rl(){return li[l++];}
	public void Clear(){li.Clear();l=0;}
	public void Again(){l=0;}
	public void Pf(){Console.WriteLine(string.Join("\n",li));}
}