#include <bits/stdc++.h>
using namespace std;
int n, e, t;
int x[100005];
long long dp[100005];
int main() {
  scanf("%d%d%d", &n, &e, &t);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &x[i]);
  }
  int pivot = 0;
  long long mn = 1000000000000000000;
  dp[0] = 0;
  for (int i = 1; i <= n; i++) {
    dp[i] = 1000000000000000000;
    for (int j = 0; j < i; j++) {
      dp[i] = min(dp[i], dp[j] + max(t, (x[i] - x[j + 1]) * 2));
    }
  }
  printf("%lld", dp[n] + e);
}
