#include <bits/stdc++.h>
using namespace std;
const int inf = 1000000;
long long mn(long long a, long long b) { return a > b ? b : a; }
int main() {
  long long n, m, k;
  while (cin >> n >> m >> k) {
    vector<long long> a(n);
    for (int i = 0; i < n; i++) {
      cin >> a[i];
    }
    long long ans = 0;
    if (n % 2 == 0) {
      ans = 0;
    } else {
      if (n / 2 >= m) {
        ans = 0;
      } else {
        ans = inf;
        for (int i = 0; i < n; i += 2) {
          ans = mn(ans, a[i]);
        }
        ans = mn(ans, k * (m / ((n / 2) + 1)));
      }
    }
    cout << ans << endl;
  }
}
