#include <bits/stdc++.h>
using namespace std;
long n, m, k, q, bst, onemove, pmove;
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> m >> k;
  bst = 1e9;
  for (int i = 1; i <= n; i++) {
    cin >> q;
    if (q < bst && i % 2 == 1) bst = q;
  }
  if (n % 2 == 0) {
    cout << 0 << endl;
    return 0;
  } else {
    onemove = n + 1;
    onemove /= 2;
    pmove = m / onemove;
    if (pmove == 0)
      bst = 0;
    else if (bst / pmove >= k)
      bst = pmove * k;
    cout << bst << endl;
  }
  cin.get();
  cin.get();
  return 0;
}
