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