Untitled

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

constexpr int SIZE = (1e+5);

ll Items[SIZE];
ll L[SIZE];

int n; ll m;

ll binary(ll target, ll level, ll items) {
    ll lo = 0, hi = target;
    while (lo <= hi) {
        ll mid = lo + (hi - lo) / 2;
        ll required_items = mid * (2 * level + mid - 1) / 2;
        if (required_items <= items) {
            lo = mid + 1;
        } else {
            hi = mid - 1;
        }
    }
    return hi;
}

void sol() {
    long long lo = 1;
    long long hi = (1e12);
    long long ans = -1;

    while (lo <= hi) {
        ll mid = lo + (hi - lo) / 2;
        ll cost = 0;
        ll tmp = m;
        bool can_make_triangle = true;
        for (int i = 0; i < n; i++) {
            if (mid > L[i]) {
                ll K = binary(mid - L[i], L[i], Items[i]) + L[i];
                if (K < mid) {
                    if (tmp >= (mid - K)){
                        tmp -= (mid - K);
                    }
                    else{
                        can_make_triangle = false;
                        break;
                    }
                }
            } else if (mid < L[i]) {
                can_make_triangle = false;
                break;
            }
        }
        if (can_make_triangle) {
            ans = mid;
            lo = mid + 1;
        } else {
            hi = mid - 1;
        }
    }
    if (ans > 0) {
        cout << ans << '\n';
    } else {
        cout << "-1\n";
    }
}

int main(void) {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    for (int i = 0; i < n; i++) {
        cin >> L[i];
    }
    for (int i = 0; i < n; i++) {
        cin >> Items[i];
    }
    sol();
    return 0;
}