#include <bits/stdc++.h>
using namespace std;
int n, m, k;
int a[100100], ma, cm;
int main() {
  int i;
  cin >> n >> m >> k;
  for (i = 0; i < n; i++) cin >> a[i];
  if (n % 2 == 0) {
    cout << "0";
    return 0;
  }
  ma = 2147483647;
  for (i = 0; i < n; i += 2) ma = min(ma, a[i]);
  cm = m / ((n + 1) / 2);
  if (cm == 0) {
    cout << "0";
    return 0;
  }
  if (ceil(ma / cm) <= k)
    cout << ma;
  else
    cout << k * cm;
  return 0;
}
