#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e17;
const ll dy[9]={0,-1,0,1,1,1,-1,-1,0};
const ll dx[9]={-1,0,1,0,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}


const int mod = MOD9;
const int max_n = 200005;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
  bool operator==(const mint &p) const { return x == p.x; }
  bool operator!=(const mint &p) const { return x != p.x; }
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
using vm=vector<mint>;
using vvm=vector<vm>;


unordered_map<ll,mint> memo;
mint PR(ll t){
    if(memo.count(t))return memo[t];
    else return memo[t]=mint(3).pow(t);
}
unordered_map<ll,mint> memo2;
mint INV(mint p){
    if(memo2.count(p.x))return memo2[p.x];
    else return memo2[p.x]=p.pow(MOD9-2);
}

namespace NTT {
    //MOD9のNTT auto c=NTT::mul(a,b)で受け取り。
	vector<mint> tmp;
	size_t sz = 1;
    mint PrimitiveRoot=3;
	struct NTTPart {
		static std::vector<mint> ntt(std::vector<mint> a, bool inv = false) {
			size_t mask = sz - 1;
			size_t p = 0;
			for (size_t i = sz >> 1; i >= 1; i >>= 1) {
				auto& cur = (p & 1) ? tmp : a;
				auto& nex = (p & 1) ? a : tmp;
				mint e = PR((MOD9 - 1) / sz * i);
				if (inv) e = INV(e);
				mint w = 1;
				for (size_t j = 0; j < sz; j += i) {
					for (size_t k = 0; k < i; ++k) {
						nex[j + k] = cur[((j << 1) & mask) + k] + cur[(((j << 1) + i) & mask) + k] * w;
					}
					w *= e;
				}
				++p;
			}
			if (p & 1) std::swap(a, tmp);
			if (inv) {
				mint invSz = INV(mint(sz));
				for (size_t i = 0; i < sz; ++i) a[i] *= invSz;
			}
			return a;
		}
		static std::vector<mint> mul(std::vector<mint> a, std::vector<mint> b) {
			a = ntt(a);
			b = ntt(b);
			for (size_t i = 0; i < sz; ++i) a[i] = a[i] * b[i];
			a = ntt(a, true);
			return a;
		}
	};
	std::vector<mint> mul(std::vector<mint> a, std::vector<mint> b) {
		size_t m = a.size() + b.size() - 1;
		sz = 1;
		while (m > sz) sz <<= 1;
		tmp.resize(sz);
		a.resize(sz, 0);
		b.resize(sz, 0);
		vector<mint> c=NTTPart::mul(a, b);
		c.resize(m);
		return c;
	}
};
vm conv(vm a,vm b){
    ll n=a.size(),m=b.size();
    vm c(n+m-1);
    rep(i,n)rep(j,m)c[i+j]+=a[i]*b[j];
    return c;
}

int main(){
    ll n,k;cin >> n >> k;
    vl v(n);rep(i,n)cin >> v[i];
    vvm dp(n+1,vm(k+1));
    dp[0][0]=1;
    rep(i,n){
        rep(j,k+1){
            if(dp[i][j]==0)continue;
            dp[i+1][j]=1;
            if(j+v[i]<=k)dp[i+1][j+v[i]]=1;
        }
    }
    vvm rdp(n+1,vm(k+1));rdp[n][0]=1;
    per(i,n){
        rep(j,k+1){
            if(rdp[i+1][j]==0)continue;
            rdp[i][j]=1;
            if(j+v[i]<=k)rdp[i][j+v[i]]=1;
        }
    }
    /*rep(i,n+1){
        rep(j,k+1)cout << dp[i][j] <<" ";cout << endl;
    }
    cout << endl;
    rep(i,n+1){
        rep(j,k+1)cout << rdp[i][j] <<" ";cout << endl;
    }*/
    if(dp[n][k]==0)cout << -1 << endl,exit(0);
    ll ans=0;
    rep(i,n){
        auto f=NTT::mul(dp[i],rdp[i+1]);
        //auto f=conv(dp[i],rdp[i+1]);
        //for(auto p:f)cout << p <<" ";cout << endl;
        if(f[k]==0)ans++;
    }
    cout << ans << endl;
}