#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
const int N = 10000002;
long long dp[N], dp2[N];
long long delivery (int n, int k, int l, int poz[]) {
for (int i = n; i >= 1; i--) poz[i] = poz[i - 1]; ///oof
for (int i = 1; i <= n; i++)
dp[i] = (i >= k ? dp[i - k] + 2 * poz[i] : 2 * poz[i]);
for (int i = n; i >= 1; i--)
dp2[i] = (i <= n - k ? dp2[i + k] + 2 * (l - poz[i]) : 2 * (l - poz[i]));
long long ans = 1e18;
for (int i = 0; i <= n; i++)
ans =min(ans, dp[i] + dp2[i + 1]);
for (int i = 0; i <= n - k; i++)
ans = min(ans, dp[i] + dp2[i + k + 1] + l);
return ans;
}
/*int main () {
int aux[] = {1, 2, 5};
cout << delivery(3, 2, 8, aux) << "\n";
}*/
