import numpy as np
N, E, T = map(int, raw_input().split())
x = np.array(map(int, raw_input().split()))

dp = np.zeros(N+1, dtype='int')
for i in range(N+1):
    if i == 0:
        dp[i] = 0
    else:
        dp[i] = (dp[0:i] + np.maximum(T, 2*(x[i-1] - x[0:i]))).min()

print dp[N] + E