#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> ti;
typedef vector<ll> li;
typedef vector<li> lii;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;
long long delivery(int n, int m, int L, int p[]) {
if(n==1)return min(p[0],L-p[0]);
vi a;
a.PB(0);
ll c=0;
int pos=0;
while(pos<n){
int x=p[pos];
if(p[pos]>L/2&&p[a.back()]<L/2&&a.back()+1!=pos)c+=L;
else if(x<=L/2)c+=x*2LL;
else c+=(L-p[a.back()+1])*2LL;
a.PB(pos);
if(pos==n-1)break;
pos+=m;
if(pos>n-1)pos=n-1;
}
ll ans=c;
int sz=a.size();
REP(j,2,m+1){
c=0;
REP(i,1,sz){
a[i]++;
if(a[i]>n-1)a[i]=n-1;
int x=p[a[i]];
if(p[a[i]]>L/2&&p[a[i-1]]<L/2&a[i-1]+1!=a[i])c+=L;
else if(x<=L/2)c+=x*2LL;
else if(a[i-1]!=n-1)c+=(L-p[a[i-1]+1])*2LL;
}
ans=min(ans,c);
}
return ans;
}
