#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
template<class S,class T> ostream& operator << (ostream& out,const pair<S,T>& o){ out << "(" << o.first << "," << o.second << ")"; return out; }
template<class T> ostream& operator << (ostream& out,const vector<T> V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; }
template<class T> ostream& operator << (ostream& out,const vector<vector<T> > Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; }
template<class S,class T> ostream& operator << (ostream& out,const map<S,T> mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; }

/*
 <url:https://yukicoder.me/problems/no/288>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */

ll solve(){
    ll res = LINF;
    ll N,M; cin >> N >> M;
    vector<ll> A(N),K(N);
    for(auto& in:A) cin >> in;
    for(auto& in:K) cin >> in;
    
    reverse(A.begin(),A.end());
    reverse(K.begin(),K.end());
    
    ll base = 1000;
    for(int i = 0; i < N;i++){
        if(M<=base)break;
        ll C = min(K[i],(M-base)/A[i]);
        M -= A[i]*C;
        K[i] -= C;
    }
    
    reverse(A.begin(),A.end());
    reverse(K.begin(),K.end());
    
    vector<ll> min_ret(base,LINF);
    min_ret[0] = 0;
    for(int i = 0; i < base;i++){
        if(min_ret[i] == LINF) continue;
        for(int j = 0; j < N;j++){
            if(i+A[j]<base){
                min_ret[i+A[j]] = min(min_ret[i+A[j]],min_ret[i]+1);
            }
        }
    }
    
    ll now = accumulate(K.begin(),K.end(),0LL);
    vector<vector<ll>> max_send(N+1,vector<ll>(2*base,-1));
    max_send[0][0] = 0;
    for(int i = 0; i < N;i++){
        for(int j = 0; j < 2*base;j++){
            if(max_send[i][j]==-1)continue;
            for(int k = 0; k <= K[i]; k++){
                if(j+A[i]*k>=2*base) break;
                max_send[i+1][j+A[i]*k] = max(max_send[i+1][j+A[i]*k],max_send[i][j]+k);
            }
        }
    }
    
    for(ll m = M; m < base; m++){
        if(max_send[N][m]==-1) continue;
        if(min_ret[m-M]==LINF) continue;
        ll c1 = max_send[N][m];
        ll c2 = min_ret[m-M];
        res = min(res,now-c1+c2);
    }
    if(res == LINF) res = -1;
    return res;
}
int main(void) {
    cin.tie(0); ios_base::sync_with_stdio(false);
    cout << solve() << endl;
    return 0;
}