#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using D = double;
using uint = unsigned int;
#ifdef WIN32
#define LLD "%I64d"
#else
#define LLD "%lld"
#endif
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
const int maxn = 1000005;
const ll inf = 1e18;
ll x[maxn], d[maxn];
int n, C;
pair<ll, int> q[maxn];
int ans1, ans2;
bool can(ll diam)
{
// cout << "can " << diam << endl;
bool needleft = false;
ll maxsum = inf;
ll minsum = -inf;
ll maxdif = inf;
ll mindif = -inf;
pair<ll, ll> mostleft = {inf, -inf};
pair<ll, ll> mostright = {-inf, -inf};
int l = 0;
int r = 0;
for (int i = 0; i < n; i++)
{
// no need to check whether it is "small" or not, because in case of "small" its square is inside "big"'s square
while (r > l && x[i] - q[l].fi + d[i] > diam)
{
int wh = q[l].se;
l++;
if (x[wh] - d[wh] < mostleft.fi - mostleft.se) mostleft = {x[wh], d[wh]};
if (x[wh] + d[wh] > mostright.fi + mostright.se) mostright = {x[wh], d[wh]};
needleft = true;
}
if (needleft)
{
maxsum = min(maxsum, (mostleft.fi + diam - C - d[i] - mostleft.se) + x[i]);
minsum = max(minsum, (mostright.fi - (diam - C - d[i] - mostright.se)) + x[i]);
maxdif = min(maxdif, x[i] - (mostright.fi - (diam - C - d[i] - mostright.se)));
mindif = max(mindif, x[i] - (mostleft.fi + diam - C - d[i] - mostleft.se));
}
while (r > l && q[r - 1].fi > x[i] - d[i]) r--;
q[r++] = {x[i] - d[i], i};
}
// cout << minsum << ' ' << maxsum << ' ' << mindif << ' ' << maxdif << endl;
if (maxsum < minsum || maxdif < mindif) return false;
return true;
}
long long find_shortcut(int N, vector <int> L0, vector <int> L, int C_)
{
n = N;
C = C_;
ll cursum = 0;
for (int i = 0; i < n; i++)
{
d[i] = L[i];
x[i] = cursum;
if (i + 1 < n) cursum += L0[i];
}
ll l = 0;
ll r = inf;
while (r - l > 1)
{
ll mid = (l + r) / 2;
if (can(mid)) r = mid;
else l = mid;
}
can(r);
return r;
}
