#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
const int MAXN = 300 * 1000;
ll a[MAXN];
ll t[MAXN];
ll b[MAXN];
ll m;
int n;
ll dziel (ll a, ll b) {
return (a/b + (a % b != 0LL));
}
bool ok (ll d) {
ll ile = 0;
ll m2 = m * ll(n);
for (int i = 0; i < n; i ++) {
t[i] = d;
}
for (int i = 0; i < n; i ++) {
if (b[i] >= a[i]) {
continue;
}
ile += min(m, dziel(d, a[i]));
t[i] -= min(m, dziel(d, a[i])) * a[i];
}
for (int i = 0; i < n; i ++) {
if (t[i] > 0LL) {
ile += dziel(t[i], b[i]);
}
}
/*cout << ile << "\n";
for (int i = 0; i < n; i ++) {
cout << t[i] << " ";
}
cout << "\n";*/
return (ile <= ll(n) * m);
}
int main () {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m;
for (int i = 0; i < n; i ++) {
cin >> a[i];
}
for (int i = 0; i < n; i ++) {
cin >> b[i];
}
ll p = 0, k = LLONG_MAX, wyn;
while (p <= k) {
ll sr = (p + k)/ 2LL;
if (ok(sr)) {
wyn = sr;
p = sr + 1;
} else {
k = sr - 1;
}
}
//cout << ok(8) << "\n";
cout << wyn << "\n";
return 0;
}
