#include "boxes.h"
#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <limits.h>
#include <set>
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 all(x) x.begin(), x.end()
#define mod 1000000007
#define inf 10000000000000
long long delivery(int n, int k, int l, int p[]) {
vl x;
set<ll> st;
x.pb(0); x.pb(l);
st.insert(0); st.insert(l);
forn(i, 0, n){
ll c = st.size();
st.insert(p[i]);
if(st.size() > c) x.pb(p[i]);
}
sort(all(x));
ll mint = l;
forn(i, 0, x.size() - 1){
mint = min(mint, 2 * (ll(l) - (ll(p[i + 1]) - ll(p[i]))));
}
return mint;
/*int ans = 0, t = 0, tt = 0;
forn(i, 0, n){
t += max(t, p[i]);
tt += min(tt, p[i]);
}
ans = min(t, tt);
return ans * 2;*/
}
