//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include "boxes.h"
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define enl printf("\n")
#define case(t) printf("Case #%d: ", (t))
#define ni(n) scanf("%d", &(n))
#define nl(n) scanf("%I64d", &(n))
#define nai(a, n) for (int i = 0; i < (n); i++) ni(a[i])
#define nal(a, n) for (int i = 0; i < (n); i++) nl(a[i])
#define pri(n) printf("%d\n", (n))
#define prl(n) printf("%I64d\n", (n))
#define pii pair<int, int>
#define pll pair<long long, long long>
#define vii vector<pii>
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef cc_hash_table<int,int,hash<int>> ht;
const double pi = acos(-1);
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;
const int MAXN = 1e7 + 5;
const double eps = 1e-9;
ll dp[MAXN][2];
ll delivery(int n, int k, int l, int a[]) {
sort(a, a + n);
for (int i = 0; i < k; i++)
dp[i][0] = min(a[i] * 2, l);
for (int i = k; i < n; i++)
dp[i][0] = dp[i - k][0] + min(a[i] * 2, l);
for (int i = n - 1; i >= n - k; i--)
dp[i][1] = min((l - a[i]) * 2, l);
for (int i = n - k - 1; i >= 0; i--)
dp[i][1] = dp[i + k][1] + min((l - a[i]) * 2, l);
ll ret = dp[0][1];
for (int i = 0; i < n; i++)
ret = min(ret, dp[i][0] + dp[i + 1][1]);
return ret;
}
/*int main()
{
return 0;
}*/
