#include <bits/stdc++.h>
using namespace std;
void run() {
  int n, m;
  long long k;
  cin >> n >> m >> k;
  if (n % 2 == 0 || m < (n + 1) / 2) {
    cout << 0 << endl;
    return;
  }
  k *= m / ((n + 1) / 2);
  for (int i = 1; i <= n; i++) {
    int tmp;
    scanf("%d", &tmp);
    if (i % 2) k = min(k, (long long)tmp);
  }
  cout << k << endl;
}
int main() { run(); }
