//https://ncode.syosetu.com/n4830bu/288/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ll N, M;
    cin >> N >> M;
    vector<ll> A(N), K(N);
    for (auto&& a : A) {
        cin >> a;
    }
    for (auto&& k : K) {
        cin >> k;
    }
    M *= -1;
    for (int i = 0; i < N; i++) {
        M += A[i] * K[i];
    }
    vector<ll> dp(610000, (ll)1e18 + 10);
    dp[0] = 0;

    ll maine = 1;
    if (M >= 0)
        while (M) {
            for (int i = 0; i < N; i++) {
                for (int x = 600000; x >= 0; x--) {
                    dp[x + A[i]] = min(dp[x + A[i]], dp[x] + maine);
                }
            }
            for (int i = 0; i < 300000; i++) {
                dp[i] = dp[i * 2 + M % 2ll];
            }
            fill(dp.begin() + 300000, dp.end(), (ll)1e18 + 10);
            M >>= 1;
            maine <<= 1;
        }
    else
        dp[0] = -1;

    cout << (dp[0] > (ll)1e18 ? -1 : dp[0]) << endl;
}