#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;


template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

template<class T> vector<T> make_vec(size_t a) { return vector<T>(a); }
template<class T, class... Ts> auto make_vec(size_t a, Ts... ts) {
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}
template<class T, class V>
typename enable_if<is_class<T>::value == 0>::type fill(T &t, const V &v) {
    t = v;
}
template<class T, class V>
typename enable_if<is_class<T>::value != 0>::type fill(T &t, const V &v){
    for (auto &e : t) fill(e, v);
}

#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }



const long long INF = 1LL<<60;

template<class Monoid> struct RMQ {
    const Monoid INF;
    int SIZE_R;
    vector<pair<Monoid,int> > dat;
    
    RMQ(int n, const Monoid &inf): INF(inf) { init(n); }
    void init(int n) {
        SIZE_R = 1;
        while (SIZE_R < n) SIZE_R *= 2;
        dat.assign(SIZE_R * 2, pair<Monoid,int>(INF, -1));
    }
    
    /* set, a is 0-indexed */
    void set(int a, const Monoid &v) { dat[a + SIZE_R] = make_pair(v, a); }
    void build() {
        for (int k = SIZE_R - 1; k > 0; --k) {
            dat[k] = min(dat[k*2], dat[k*2+1]);
        }
    }
    
    /* update, a is 0-indexed */
    void update(int a, const Monoid &v) {
        int k = a + SIZE_R;
        dat[k] = make_pair(v, a);
        while (k >>= 1) dat[k] = min(dat[k*2], dat[k*2+1]);
    }
    
    /* get {min-value, min-index}, a and b are 0-indexed */
    pair<Monoid,int> get(int a, int b) {
        pair<Monoid,int> vleft = make_pair(INF, -1), vright = make_pair(INF, -1);
        for (int left = a + SIZE_R, right = b + SIZE_R; left < right; left >>= 1, right >>= 1) {
            if (left & 1) vleft = min(vleft, dat[left++]);
            if (right & 1) vright = min(dat[--right], vright);
        }
        return min(vleft, vright);
    }
    inline Monoid operator [] (int a) { return dat[a + SIZE_R].first; }
    
    /* debug */
    void print() {
        for (int i = 0; i < SIZE_R; ++i) {
            Monoid val = (*this)[i];
            if (val < INF) cout << val;
            else cout << "INF";
            if (i != SIZE_R-1) cout << ",";
        }
        cout << endl;
    }
};



int N;
long long T, E;
vector<long long> x;

long long solve() {
    vector<long long> dp(N+1, INF);
    RMQ<long long> r1(N+1, INF), r2(N+1, INF);
    dp[0] = 0;
    r1.update(0, -x[0] * 2);
    r2.update(0, 0);
    for (int i = 1; i <= N; ++i) {
        int ut = upper_bound(x.begin(), x.end(), x[i-1] - (T+1)/2) - x.begin() - 1;
        int lt = lower_bound(x.begin(), x.end(), x[i-1] - (T-1)/2) - x.begin();
        chmin(ut, i-1);
        chmin(dp[i], r1.get(0, ut+1).first + x[i-1] * 3);
        chmin(dp[i], r2.get(lt, i).first + x[i-1] + T);
        r1.update(i, dp[i] - x[i] * 2 - x[i-1]);
        r2.update(i, dp[i] - x[i-1]);

        //cout << i << ": " << dp[i] << endl; r1.print(); r2.print();
    }
    return dp[N] + (E - x[N-1]);
}

int main() {
    while (cin >> N >> E >> T) {
        x.resize(N);
        for (int i = 0; i < N; ++i) cin >> x[i];
        cout << solve() << endl;
    }
}


Measured memory_bytes: 9984