#include <bits/stdc++.h>
using namespace std;
const long long N = 1e5 + 5;
const long long INF = 1e15;
const int MOD = 1e9 + 7;
const double EPS = 1e-7;
const double PI = acos(-1.0);
long long n, m, k, a;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL), cout.tie(NULL);
  cin >> n >> m >> k;
  if ((n & 1) == 0)
    cout << 0 << '\n';
  else {
    long long minn = LLONG_MAX;
    for (int i = 0; i < n; i++) {
      cin >> a;
      if ((i & 1) == 0) minn = min(minn, a);
    }
    cout << min(minn, k * (m / (n / 2 + 1))) << '\n';
  }
}
