#include <bits/stdc++.h>
using namespace std;
const int inf = (int)1e9;
const long long linf = (long long)1e18;
const long double pi = acos(-1.0);
const double eps = 1e-9;
const long long osn = (long long)1e18;
inline void finclude() { srand(time(NULL)); }
long long min(long long a, long long b) {
  if (a < b) return a;
  return b;
}
int main() {
  finclude();
  long long n, m, k, s = (long long)1e18, a;
  cin >> n >> m >> k;
  for (int i = 0; i < n; ++i) {
    cin >> a;
    if (i % 2 == 0) s = min(s, a);
  }
  if (n % 2 == 0) {
    cout << 0 << '\n';
    return 0;
  }
  cout << min(s, ((2 * m) / (n + 1)) * k) << '\n';
  return 0;
}
