#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k, mp;
  cin >> n >> m >> k;
  mp = n / 2 + 1;
  if (n % 2 == 0 || mp > m) {
    cout << 0;
    return 0;
  }
  int ans = 0, i, a[10005];
  for (i = 0; i < n; i++) cin >> a[i];
  int min = a[0];
  for (i = 0; i < n; i++)
    if (i % 2 == 0)
      if (a[i] < min) min = a[i];
  for (i = 0; i < k; i++) {
    int num = m / mp;
    if (min == 0) break;
    if (num <= min) {
      min -= num;
      ans += num;
    } else {
      ans += min;
      min = 0;
    }
  }
  cout << ans;
  return 0;
}
