#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef tuple <ll,ll,ll> plll;
typedef vector <plll> vplll;
typedef pair <ll,ll> pll;
typedef vector <ll> vll;
typedef vector <pll> vpll;
typedef vector <vector <pll>> vvpll;
typedef vector <vector <ll>> vvll;
typedef vector <bool> vb;
typedef vector <vector <bool>> vvb;
#define loop(i, s, e) for (ll i = (s); i < (e); ++i)
#define loopr(i, e, s) for (ll i = (e)-1; i >= (s); --i)
#define all(a) a.begin(), a.end()
const ll inf = 1e20;
ll n,k,l;
vll p;
vll r;
long long delivery(int N, int K, int L, int P[]) {
n=N,k=K,l=L;
p.resize(n);
r.resize(n);
loop(i,0,n) {
p[i] = P[i];
r[i] = l-p[i];
}
sort(all(p));
sort(all(r));
vll suml(n), sumr(n);
{
vb new_round(n);
ll in = 0, rounds = 0, mx = 0;
loopr(i,n,0) {
in++;
ll pos = p[i];
if (rounds*k >=in ) {// do not open
suml[i] = mx;
}
else {//open new
new_round[i] = 1;
suml[i] = pos + min(pos, l-pos);
mx = suml[i];
rounds++;
}
}
ll sum = 0;
loop(i,0,n) {
suml[i]+=sum;
if (new_round[i]) {
sum+=suml[i];
}
}
}
{
vb new_round(n);
ll in = 0, rounds = 0, mx = 0;
loopr(i,n,0) {
in++;
ll pos = r[i];
if (rounds*k >=in ) {// do not open
sumr[i] = mx;
}
else {//open new
new_round[i] = 1;
sumr[i] = l-pos + min(pos, l-pos);
mx = sumr[i];
rounds++;
}
}
ll sum = 0;
loop(i,0,n) {
sumr[i]+=sum;
if (new_round[i]) {
sum+=sumr[i];
}
}
}
ll ans = inf;
reverse(all(sumr));
suml.push_back(0);
sumr.push_back(0);
loop(i,0,n) {
ans = min(ans,suml[i] + sumr[(i+1)]);
}
ans = min(ans, sumr[0]);
return ans;
}
