#include "boxes.h"
#include<bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include "/home/ioi/codes/ioi15_d1/debug.h"
#else
#define debug(...) void(37)
#endif
template<typename T>
vector<T> inverse_fuck(T* a, int N) {
vector<T> res(N);
for (int i = 0; i < N; ++i) {
res[i] = a[i];
}
return res;
}
long long delivery(int N, int K, int L, int __p[]) {
vector<int> P = inverse_fuck(__p, N);
debug(N, K, L, P);
int mid = 0;
vector<int> left, right;
for (int i = 0; i < N; ++i) {
if (P[i] == 0) {
//
} else if (L % 2 == 0 && P[i] == L / 2) {
mid += 1;
} else {
(P[i] <= L / 2 ? left : right).push_back(P[i]);
}
}
int sl = int(left.size()), sr = int(right.size());
vector<long long> best_l(sl + 1);
vector<long long> best_r(sr + 1);
for (int i = 1; i <= sl; ++i) {
best_l[i] = best_l[max(0, i - K)] + 2 * left[i - 1];
}
for (int i = sr - 1; i >= 0; --i) {
best_r[i] = best_r[min(sr, i + K)] + 2 * (L - right[i]);
}
debug(left, right, best_l, best_r);
long long ans = 1LL * ((mid + K - 1) / K) * L;
mid %= K;
auto Solve = [&](int out) {
const long long inf = (long long) 1e17;
long long res = inf;
for (int i = 0; i <= min(sl, out); ++i) {
res = min(res, best_l[max(0, sl - i)] + best_r[min(sr, out - i)]);
}
debug(out, res);
return res;
};
ans += min({(mid ? Solve(K - mid) : Solve(0)), (mid ? Solve(2 * K - mid) : Solve(K) + L)});
debug(ans);
return ans;
}
