#include <bits/stdc++.h>
using namespace std;
const int inf = 2000000000, mod = 1000000007;
const double eps = 0.000001;
int main() {
  long long n, m, k;
  cin >> n >> m >> k;
  vector<long long> a(n);
  for (long long i = 0; i < n; i++) cin >> a[i];
  if (n % 2 == 0) {
    cout << 0;
    return 0;
  }
  long long mi = inf;
  for (long long i = 0; i < n; i += 2) mi = min(mi, a[i]);
  long long ma = (2 * m) / (n + 1);
  cout << min(mi, min(ma, mi) * k);
  return 0;
}
