#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <limits.h>
#include "boxes.h"
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
typedef vector<pii> vii;
typedef map<int, int> mii;
typedef vector<vl> vvl;
typedef pair<ll, ll> pll;
typedef vector<pll> vpl;
#define F first
#define S second
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define pb push_back
#define forn(i, x, n) for(ll i = x; i < n; i++)
#define fornl(i, x, n) for(ll i = x; i >= n; i++)
#define mod 1000000007
#define inf 10000000000000
long long delivery(int n, int k, int l, int p[]) {
int ans = 0, t = 0, tt;
forn(i, 0, n){
t += max(t, p[i]);
tt += min(tt, p[i]);
}
ans = min(t, tt);
return ans * 2;
}
