#include <bits/stdc++.h>
using namespace std;
int d[100000];
int main() {
  int i, n, l = 100000000;
  long long k, m;
  cin >> n >> m >> k;
  for (i = 0; i < n; i++) {
    scanf("%d", &d[i]);
    if (!(i & 1)) l = min(l, d[i]);
  }
  m /= ((n + 1) >> 1);
  l = min((long long)(l), m * k);
  if (!(n & 1)) l = 0;
  cout << l << '\n';
  return 0;
}
