#include <bits/stdc++.h>
#define SZ(x) ((int) (x).size())
using namespace std;

typedef long long i64;

const int64_t LINF = 1LL << 62;

int main() {
    #ifdef LOCAL_RUN
    freopen("task.in", "r", stdin);
    freopen("task.out", "w", stdout);
    //freopen("task.err", "w", stderr);
    #endif // ONLINE_JUDGE
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n, E, T;
    cin >> n >> E >> T;

    vector<int> X(n + 1, 0);
    for (int i = 1; i <= n; ++i) {
        cin >> X[i];
    }

    vector<int64_t> dp(n + 1, 0);
    deque<pair<int, int64_t>> d;
    for (int i = 1; i <= n; ++i) {
        dp[i] = LINF;
        int j = i - 1;
        int64_t time = -LINF;
        int64_t cval = dp[j] + X[j + 1] - X[j] + 
                3LL * (X[i] - X[j + 1]) +
                max((int64_t) 0, (int64_t) (T - 2LL * (X[i] - X[j + 1])));
        int64_t currSteady = T + 2 * X[j + 1];
        while (!d.empty()) {
            int p = d.back().first;
            int64_t pval = dp[p] + X[p + 1] - X[p] + 
                    3LL * (X[i] - X[p + 1]) +
                    max((int64_t) 0, (int64_t) (T - 2LL * (X[i] - X[p + 1])));
            if (cval <= pval) {
                d.pop_back();
                continue;
            }
            int64_t prevSteady = T + 2 * X[p + 1];
            time = max(prevSteady, 2LL * X[i]) + cval - pval;
            if (time > currSteady) {
                time = LINF;
            }
            if (time <= d.back().second) {
                d.pop_back();
            } else {
                break;
            }
        }
        if (d.empty()) {
            time = -LINF;
        }
        d.push_back(make_pair(j, time));
        while (SZ(d) > 1 && 2 * X[i] >= d[1].second) {
            d.pop_front();
        }
        d.front().second = -LINF;
        int p = d.front().first;
        int64_t pval = dp[p] + X[p + 1] - X[p] + 
                3LL * (X[i] - X[p + 1]) +
                max((int64_t) 0, (int64_t) (T - 2LL * (X[i] - X[p + 1])));
        dp[i] = pval;
    }
    int64_t ans = dp[n] + E - X[n];
    cout << ans << '\n';
}