#include "boxes.h"
#include "bits/stdc++.h"
using namespace std;
long long delivery(int N, int K, int L, int p[]) {
vector<int> vl, vr;
for (int i = 0; i < N; ++i) {
if (p[i] <= L / 2) vl.push_back(p[i]);
else vr.push_back(p[i]);
}
sort(vl.begin(), vl.end());
sort(vr.begin(), vr.end());
vector<long long> sum(K), sum2(K);
int sl = (int) vl.size(), sr = (int) vr.size();
for (int i = 0; i < sl; ++i) {
sum[i % K] += vl[i] * 2;
}
for (int i = 0; i < sr; ++i) {
sum2[i % K] += (L - vr[i]) * 2;
}
long long ret = (!sl ? 0 : sum[(sl - 1) % K]);
ret += sum2[0];
for (int i = 1; i < K; ++i) {
long long tmp = L;
if (sl - i - 1 >= 0) {
tmp += sum[(sl - i - 1) % K];
}
tmp += sum2[K - i];
ret = min(ret, tmp);
}
return ret;
}
