#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include "boxes.h"
using namespace std;
#define all(a) (a).begin(), (a).end()
#define sz(a) (int)(a).size()
#define ll long long
#define ld long double
#define ui uint64_t
#define cont(set, element) ((set).find(element) != (set).end())
/********* DEBUG *********/
template <typename T>
void outvec(const vector<T>& Z){
for (const T& x : Z)
cout << x << ' ';
cout << "\n";
}
void printVariable(const any& var) {
if (!var.has_value()) {
cout << "null";
return;
}
if (var.type() == typeid(int)) {
cout << any_cast<int>(var);
} else if (var.type() == typeid(double)) {
cout << any_cast<double>(var);
} else if (var.type() == typeid(float)) {
cout << any_cast<float>(var);
} else if (var.type() == typeid(char)) {
cout << any_cast<char>(var);
} else if (var.type() == typeid(bool)) {
cout << (any_cast<bool>(var) ? "true" : "false");
} else if (var.type() == typeid(string)) {
cout << any_cast<string>(var);
} else if (var.type() == typeid(const char*)) {
cout << any_cast<const char*>(var);
} else if (var.type() == typeid(long long)) {
cout << any_cast<long long>(var);
} else {
cout << "[unknown type]";
}
}
template<typename... Args>
void outval(Args... args) {
vector<any> variables = {args...};
for (size_t i = 0; i < variables.size(); ++i) {
printVariable(variables[i]);
if (i != variables.size() - 1) {
cout << " ";
}
}
cout << "\n";
}
#define nl "\n"
#define sp << " " <<
/********* DEBUG *********/
const ll MOD = 1000000007;
const ll inf = 1e18;
const ll mxN = 1000005;
// just try every possible split
ll delivery(int N, int K, int L, int p[]) {
if (L == 1)
return 0;
vector<ll> left(N), right(N);
for (int i = 0; i < N; i++){
left[i] = p[i] <= L/2 ? p[i] * 2 : L;
if (i >= K)
left[i] += left[i-K];
}
//outvec(left);
for (int i = N-1; i >= 0; i--){
right[i] = p[i] <= L/2 ? L : (L-p[i])*2;
if (i <= N-K-1)
right[i] += right[i+K];
}
//outvec(right);
ll ans = min(left[0] + right[1], right[N-1] + left[N-2]);
for (int i = 1; i < N-1; i++)
ans = min(ans, left[i] + right[i+1]);
return ans;
}
