#include <bits/stdc++.h>
using namespace std;
long long n, m, k;
int num[10000];
int main() {
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) cin >> num[i];
  if (n % 2 == 0)
    cout << "0" << endl;
  else {
    int maxnum = num[0];
    for (int i = 0; i < n; i += 2)
      if (num[i] < maxnum) maxnum = num[i];
    long long step = m / (n / 2 + 1);
    cout << (step * k < maxnum ? step * k : maxnum) << endl;
  }
  return 0;
}
