#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pair<int,int>> vpi;
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
#define pb push_back
#define rsz resize
#define sz(x) int(x.size())
#define all(x) begin(x), end(x)
#define fi first
#define se second
int const N=1e7+3;
int cwcnt[N];
int ccwcnt[N];
ll cw[N];
ll ccw[N];
ll delivery(int n, int k, int L, int p[]) {
cwcnt[0]=0;
cw[0]=0;
FOR(i,1,n+1)
{
cwcnt[i]=cwcnt[i-1]+1;
cw[i]=cw[i-1];
if(cwcnt[i]>k)
{
cwcnt[i]=1;
cw[i]+=p[i-1]*2;
}
else
{
if(i-2>=0)cw[i]+=(p[i-1]-p[i-2])*2;
else cw[i]+=p[i-1]*2;
}
}
ccwcnt[0]=0;
ccw[0]=0;
FOR(i,1,n+1)
{
ccwcnt[i]=ccwcnt[i-1]+1;
ccw[i]=ccw[i-1];
if(ccwcnt[i]>k)
{
ccwcnt[i]=1;
ccw[i]+=(L-p[n-i])*2;
}
else
{
if(n-i+1<n)ccw[i]+=(p[n-i+1]-p[n-i])*2;
else ccw[i]+=(L-p[n-i])*2;
}
}
ll ans=4e18;
F0R(i,n+1)
{
ll cand=cw[i]+ccw[n-i];
ans=min(ans,cand);
}
F0R(i,n+1)
{
ll cand=cw[i]+L;
if(n-i-k>=0)cand+=ccw[n-i-k];
ans=min(ans,cand);
}
return ans;
}
