#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
long long delivery(int N, int K, int L, int p[]) {
if (N <= 10) {
int per[N];
iota(per, per + N, 0);
long long ans = 9e18;
do {
long long res = 0;
int mx = 0;
for (int i = 0; i < N; ++i) {
if (i % K == 0) {
res += min(2 * mx, L);
mx = 0;
}
mx = max(mx, p[per[i]]);
}
res += min(2 * mx, L);
ans = min(ans, res);
} while (next_permutation(per, per + N));
return ans;
}
long long ans, A[N], A2[N], KS = 0;
for (int i = 0; i < N; ++i) {
if (i % K == 0 && i) {
KS += min(2 * p[i - 1], L);
}
A[i] = KS + min(2 * p[i], L);
}
KS = 0;
for (int i = N - 1; ~i; --i) {
if ((N - i - 1) % K == 0 && i < N - 1) {
KS += min(2 * (L - p[i + 1]), L);
}
A2[i] = KS + min(2 * (L - p[i]), L);
}
ans = min(A[N - 1], A2[0]);
for (int i = 0; i < N - 1; ++i) {
ans = min(ans, A[i] + A2[i + 1]);
}
return ans;
}
