#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 = items;
while (lo <= hi) {
ll mid = lo + (hi - lo) / 2;
ll required_items = (mid) * (level + level + mid - 1) / 2;
if (required_items >= target) {
hi = mid - 1;
} else {
lo = mid + 1;
}
}
return lo;
}
void sol() {
long long lo = 1;
long long hi = (1e18);
long long ans = -1;
while (lo + 1 < hi) {
ll mid = lo + (hi - lo) / 2;
ll cost = 0;
for (int i = 0; i < n; i++) {
if (mid > L[i]) {
ll K = binary(mid - L[i], L[i], Items[i]); // 현재 아이템으로 키울 수 있는 레벨의 최댓값
if(L[i] + K >= mid){
continue;
}
cost += mid - L[i] - K; // 필요한 성장 비뱍의 개수
}
}
if (cost <= m && mid > 0) {
lo = mid + 1;
ans = mid;
} else {
hi = mid - 1;
}
}
cout << ans << '\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;
}