#include <bits/stdc++.h>
using namespace std;
const long double PI = 3.1415926535897932384626433832795;
const int INF = (1 << 30) - 1;
int getint() {
  unsigned int c;
  int x = 0;
  while (((c = getchar()) - '0') >= 10) {
    if (c == '-') return -getint();
    if (!~c) exit(0);
  }
  do {
    x = (x << 3) + (x << 1) + (c - '0');
  } while (((c = getchar()) - '0') < 10);
  return x;
}
int main() {
  ios_base::sync_with_stdio(false);
  long long n, m, k, i;
  cin >> n >> m >> k;
  long long minimum = INF, aux;
  for (i = 1; i <= n; i++) {
    cin >> aux;
    if (i % 2 == 1) minimum = min(minimum, aux);
  }
  if (n % 2 == 0)
    cout << 0 << endl;
  else
    cout << min(minimum, k * ((m * 2) / (n + 1))) << endl;
  return 0;
}
