#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include "boxes.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/* DEFINES */
#define S second
#define F first
#define ll long long
#define ull unsigned long long
#define ld long double
#define npos ULLONG_MAX
#define INF LLONG_MAX
#define vv(a) vector<a>
#define pp(a, b) pair<a, b>
#define pq(a) priority_queue<a>
#define qq(a) queue<a>
#define ss(a) set<a>
#define mm(a, b) map<a, b>
#define ump(a, b) unordered_map<a, b>
#define sync \
ios_base::sync_with_stdio(0); \
cin.tie(0); \
cout.tie(0);
#define elif else if
#define endl "\n"
#define allc(a) begin(a), end(a)
#define all(a) a, a + sizeof(a) / sizeof(a[0])
#define pb push_back
#define logi(a) __lg(a)
#define sqrt(a) sqrtl(a)
#define mpr make_pair
#define ins insert
using namespace std;
using namespace __gnu_pbds;
using namespace __cxx11;
typedef char chr;
typedef basic_string<chr> str;
template <typename T, typename key = less<T>>
using ordered_set = tree<T, null_type, key, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll delivery(int n, int k, int L, int p[]) {
int l = 0, r = n - 1;
ll ans = 0;
while (l <= r)
{
k = min(k, r - l + 1);
if (p[l + k - 1] + min(L - p[l + k - 1], p[l + k - 1]) < L - p[r - k + 1] + min(L - p[r - k + 1], p[r - k + 1]))
ans += p[l + k - 1] + min(L - p[l + k - 1], p[l + k - 1]), l += k;
else
ans += L - p[r - k + 1] + min(L - p[r - k + 1], p[r - k + 1]), r -= k;
}
return ans;
}
