#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, B;
    cin >> n >> B;
    ll ok = 0, ng = 0;
    vector<pair<int,int>> a(n);
    for(int i = 0; i < n; i++) cin >> a[i].first;
    for(int i = 0; i < n; i++) cin >> a[i].second, ng += a[i].second;
    sort(a.begin(), a.end());
    ng++;
    while(ok + 1 < ng){
        ll mid = (ok + ng) / 2;
        vector<ll> cnt(n);
        vector<pair<int,int>> b;
        ll r = mid, cur = 0;
        for(int i = 0; i < n && r >= 1; i++){
            int d = min((ll)a[i].second, r);
            r -= d;
            cur += (ll)(d) * a[i].first;
            cnt[i] = d;
            b.emplace_back(a[i].first, d);
        }

        reverse(b.begin(), b.end());
        int m = b.size();
        vector<ll> sv(m + 1), sv2(m + 1);
        for(int i = 0; i < m; i++){
            sv[i + 1] = sv[i] + b[i].second;
            sv2[i + 1] = sv2[i] + b[i].first * (ll)(b[i].second);
        }

        ll mn = cur;
        for(int i = 0; i < n; i++){
            if(a[i].second >= mid){
                mn = mid;
                break;
            }
            if(cnt[i] == a[i].second){
                mn = min(mn, cur - a[i].second * (a[i].first - 1));
            }else{
                // 大きい方からa[i].second個を1にする
                // 0 2 5
                int p = lower_bound(sv.begin(), sv.end(), a[i].second) - sv.begin();
                p--;
                mn = min(mn, cur - (sv2[p] + (a[i].second - sv[p]) * b[p].first) + a[i].second);
            }
        }
        (B >= mn ? ok : ng) = mid;
    }
    cout << ok << '\n';
}