#include "boxes.h"
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")
#pragma GCC target("popcnt")
using namespace std;
using ll = long long;
using ull = unsigned long long;
using lld = long double;
using ii = pair<int,int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
using vii = vector<ii>;
using vpll = vector<pll>;
using vlld = vector<lld>;
#define all(x) x.begin(),x.end()
#define lsb(x) x&(-x)
#define gcd(a,b) __gcd(a,b)
#define sz(x) (int)x.size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fls cout.flush()
#define fore(i, l, r) for (auto i = l; i < r; i++)
#define fo(i, n) fore (i, 0, n)
#define forex(i, r, l) for (auto i = r-1; i >= l; i--)
#define ffo(i, n) forex (i, n, 0)
bool cmin(ll &a, ll b) { if (b < a) { a=b; return 1; } return 0; }
bool cmax(ll &a, ll b) { if (b > a) { a=b; return 1; } return 0; }
const ll INF = 1e18;
long long delivery(int n, int k, int l, int p[]) {
deque<ll> A, B;
fo (i, n) {
if (p[i] <= l/2) A.pb(p[i]);
else B.pb(p[i]);
}
reverse(all(B));
ll ans = 0;
while (A.size() >= k) {
ans += A[k-1] * 2ll;
ll cnt = k;
while (cnt--) A.pop_front();
}
while (B.size() >= k) {
ans += (l - B[k-1] + 1) * 2ll;
ll cnt = k;
while (cnt--) B.pop_front();
}
if (A.size() + B.size() == 0) return ans;
ll nans = (A.size() > 0 ? A.back()*2ll : 0ll) + (B.size() > 0 ? (l - B.back() + 1)*2ll : 0ll);
nans = min(nans, l*2ll + (A.size()+B.size() > k ? (l - B[A.size()+B.size()-k-1] + 1) * 2ll : 0));
nans = min(nans, l*2ll + (A.size()+B.size() > k ? (A[A.size()+B.size()-k-1]) * 2ll : 0));
ans += nans;
return ans;
}
