//#include <bits/stdc++.h>
#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
//#include "boost/multiprecision/cpp_int.hpp"
//typedef boost::multiprecision::cpp_int LL;
typedef long double dd;
#define i_7 (ll)(1E9+7)
//#define i_7 998244353
#define i_5 i_7-2
ll mod(ll a){
    ll c=a%i_7;
    if(c>=0)return c;
    return c+i_7;
}
typedef pair<ll,ll> l_l;
typedef pair<dd,dd> d_d;
ll inf=(ll)1E16;
#define rep(i,l,r) for(ll i=l;i<=r;i++)
#define pb push_back
ll max(ll a,ll b){if(a<b)return b;else return a;}
ll min(ll a,ll b){if(a>b)return b;else return a;}
void Max(ll &pos,ll val){pos=max(pos,val);}//Max(dp[n],dp[n-1]);
void Min(ll &pos,ll val){pos=min(pos,val);}
void Add(ll &pos,ll val){pos=mod(pos+val);}
dd EPS=1E-9;
#define fastio ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define fi first
#define se second
#define endl "\n"
#define SORT(v) sort(v.begin(),v.end())
#define ERASE(v) v.erase(unique(v.begin(),v.end()),v.end())
#define POSL(v,x) (lower_bound(v.begin(),v.end(),x)-v.begin())
#define POSU(v,x) (upper_bound(v.begin(),v.end(),x)-v.begin())
template<class T>
inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return true;
    }
    return false;
}


void mod_print(ll k){
    ll P=1000;
    rep(y,1,P){
        ll x=mod(y*k);
        if(x+P>=i_7){
            x-=i_7;
        }
        if(abs(x)<=P){
            cout<<x<<"/"<<y<<endl;
            return;
        }
    }
    cout<<"nun"<<endl;
}
//////////////////////////




template<typename T, typename Func_mv>
struct Segtree {
    ll n, n_org;
    vector<T> dat;
    Func_mv merge_values;  //dataとdataの演算
    T te; //dataの単位元かつ初期値
 
    Segtree(){}
    Segtree(ll n_org,
                Func_mv merge_values,
                T te):
                n_org(n_org),
                merge_values(merge_values),
                te(te){
        n = 1;
        while(n < n_org) n <<= 1;
        dat.resize(2*n-1, te);
    }
 
    void build(vector<T>& A){
        for(ll k=0; k<ll(A.size()); k++) dat[k+n-1] = A[k];
        for(ll k=n-2; k>=0; k--) dat[k] = merge_values(dat[2*k+1], dat[2*k+2]);
    }
    void update(ll k, T x){ //位置kの要素を更新
        k+=n-1;
        dat[k]=x;
        while(k>0){
            k=(k-1)/2;
            dat[k]=merge_values(dat[2*k+1],dat[2*k+2]);
        }
    }
    void add(ll k,T x){//位置kの要素に加算
        k+=n-1;
        dat[k]+=x;
        while(k>0){
            k=(k-1)/2;
            dat[k]=merge_values(dat[2*k+1],dat[2*k+2]);
        }
    }
    T get(ll a, ll b){ //[a,b]から(最小値とか和とかを)get
        return query(a, b+1, 0, 0, n);
    }
    
private:
    T query(ll a, ll b, ll k, ll lb, ll rb){
        if(rb<=a || b<=lb) return te;
        if(a<=lb && rb<=b) return dat[k];
        ll mb = (lb+rb)>>1;
        T vl = query(a, b, 2*k+1, lb, mb);
        T vr = query(a, b, 2*k+2, mb, rb);
        return merge_values(vl, vr);
    }
};
auto make_segtree = [](ll N){ //auto make_segtree = [&](ll N)
    //点更新と区間最小
    using T = ll;
    auto merge_values = [](T& a, T& b){return min(a, b);};
    T te = inf;
    return Segtree<T, decltype(merge_values)>
        (N, merge_values, te);
};
/*
auto st = make_segtree(n);
vector<ll> init(n);
st.build(init);
 */

int main(){fastio
    ll n,e,t;cin>>n>>e>>t;
    vector<ll>x(n+1);
    rep(i,0,n-1)cin>>x[i];
    x[n]=e;
    auto ep=make_segtree(n+1);
    ep.update(0,-2*x[0]);
    rep(i,1,n){
        ll k=POSL(x,(2*x[i-1]-t+1)/2)-1;
        ll res=x[i]+2*x[i-1]+ep.get(0,k);
        
        ll res2=ep.get(i-1,i-1)+3*x[i-1]+t+(x[i]-x[i-1]);
        if(k+1<i)chmin(res2,((ep.get(k+1,k+1)+3*x[k+1])+x[i]-x[k+1]+t));
        ep.update(i,min(res,res2)-3*x[i]);
    }
    
    //rep(i,0,n)cout<<ep.get(i,i)<<" ";cout<<endl;
    //rep(i,0,n)cout<<ep.get(i,i)+3*x[i]<<" ";cout<<endl;
    cout<<ep.get(n,n)+3*x[n]<<endl;
    return 0;
}


Measured memory_bytes: 3072