#include <bits/stdc++.h>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define FORR(i,a,b) for (int i=(a);i>=(b);i--)
#define pb push_back

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef set<int> si;
const ll inf = 1e18;
const int mod = 1e9+7;

ll dp[250001];
ll n, m, a[500], k[500], q;

main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n >> m;
  FOR(i, 0, n)cin >> a[i];
  FOR(i, 0, n)cin >> k[i];
  q = a[n - 1];
  q *= q;
  FOR(i, 1, q)dp[i] = inf;
  m *= -1;
  FOR(i, 0, n)m += a[i] * k[i];
  if(m < 0){
    cout << -1 << endl;
    return 0;
  }
  FORR(i, n-1, 0){
    ll d = a[i];
    FOR(j, d, q){
      dp[j] = min(dp[j], dp[j - d] + 1);
    }
  }
  ll t = 0;
  if(m >= q){
    t = (m - q)/a[n-1] + 1;
    m -= t * a[n-1];
  }
  t += dp[m];
  if(t >= inf)t = -1;
  cout << t << endl;
}