#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
//#include<cctype>
#include<climits>
#include<iostream>
#include<string>
#include<vector>
#include<map>
//#include<list>
#include<queue>
#include<deque>
#include<algorithm>
//#include<numeric>
#include<utility>
#include<complex>
//#include<memory>
#include<functional>
#include<cassert>
#include<set>
#include<stack>

const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;

const int MAXN = 501;
const ll INF = 1ll<<55;
int A[MAXN];
ll K[MAXN];
int N;
ll M;

ll dp[MAXN*MAXN];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> N >> M;
    ll sum = 0;
    for (int i = 0; i < N; i++) cin >> A[i];
    for (int i = 0; i < N; i++) {
        cin >> K[i];
        sum += A[i]*K[i];
    }
    if (sum < M) {
        cout << -1 << endl;
        return 0;
    }
    for (int j = 0; j <= A[N-1]*A[N-1]; j++) dp[j] = INF;
    dp[0] = 0;
    for (int i = 0; i < N; i++) for (int j = 0; j <= A[N-1]*A[N-1]; j++) {
        if (A[i] <= j) dp[j] = min(dp[j], dp[j-A[i]] + 1);
    }
    ll ans = 0;
    ll T = sum-M;
    if (T > A[N-1]*A[N-1]) {
        ll cnt = T-A[N-1]*A[N-1];
        ans += cnt/A[N-1]+1;
        T -= ans*A[N-1];
    }
    ans += dp[T];
    if (ans >= INF) ans = -1;
    cout << ans << endl;
    return 0;
}