#include <bits/stdc++.h>
#define pb push_back
using namespace std;
#include "boxes.h"
const long long inf = 1e17;
long long delivery(int N, int K, int L, int p[]) {
vector<int> pos;
for(int i = 0; i < N; i++){
pos.pb(p[i]);
}
vector<int> dpl(N+1), dpr(N+1);
for(int i = 1; i <= N; i++){
if(i < K) dpl[i] = pos[i-1] * 2;
else dpl[i] = dpl[i - K] + pos[i-1] * 2;
}
for(int i = 1; i <= N; i++){
if(i < K) dpr[i] = (L - pos[N-i]) * 2;
else dpr[i] = dpr[i - K] + (L - pos[N-i]) * 2;
}
long long ans = inf;
for(int l = 0; l <= N; l++){
for(int r = 0; r <= N-l; r++){
int rem = N - l - r;
long long calc = dpl[l] + dpr[r] + ((rem + K - 1)/K) * L;
//cout<<"l = "<<lop[l].first<<" "<<lop[l].second<<" r = "<<rop[r].first<<" "<<rop[r].second<<" calc = "<<calc<<endl;
ans = min(ans, calc);
}
}
return ans;
}
