#include <bits/stdc++.h>
using ll = long long;
int main()
{
    int N;
    ll M;
    std::cin >> N >> M;
    std::vector<int> A(N);
    std::vector<ll> K(N);
    for (int i = 0; i < N; i++) { std::cin >> A[i]; }
    for (int i = 0; i < N; i++) { std::cin >> K[i], M -= K[i] * A[i]; }
    M = -M;
    ll ans = (std::max(0LL, M - A[N - 1] * A[N - 1] + A[N - 1]) / A[N - 1]);
    M -= ans * A[N - 1];
    std::vector<int> memo(A[N - 1] * A[N - 1], A[N - 1] * A[N - 1]);
    auto dp = [&](auto&& self, const ll M) -> int {
        if (M == 0) { return 0; }
        if (M < 0) { return A[N - 1] * A[N - 1]; }
        if (memo[M] != A[N - 1] * A[N - 1]) { return memo[M]; }
        int ans = A[N - 1] * A[N - 1];
        for (const ll a : A) { ans = std::min(ans, self(self, M - a)); }
        return memo[M] = ans + 1;
    };
    const int add = dp(dp, M);
    if (add >= A[N - 1] * A[N - 1]) { return std::cout << -1 << std::endl, 0; }
    std::cout << ans + add << std::endl;
    return 0;
}