#include <bits/stdc++.h>
const int N = 100010;
const int inf = 0x3f3f3f3f;
using namespace std;
int n, m, k, a[N];
int main() {
  while (scanf("%d%d%d", &n, &m, &k) == 3) {
    for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
    if (n % 2 == 0 || (n + 1) / 2 > m) {
      puts("0");
      return 0;
    }
    long long s = (n + 1) / 2;
    s = m / s;
    s *= k;
    int mn = inf;
    for (int i = 1; i <= n; i += 2) mn = min(mn, a[i]);
    printf("%I64d\n", min(mn + 0ll, s));
  }
  return 0;
}
