n, e, t = map(int, input().split())
x = list(map(int, input().split()))
dp = [0] + [float('inf')] * n
for i in range(n):
    ndp = dp.copy()
    for j in range(i, n):
        ndp[j + 1] = min(dp[j + 1], dp[i] + max(t, 2 * (x[j] - x[i])))
    dp = ndp
print(e + dp[-1])
