#include <bits/stdc++.h>
using namespace std;
int num[10005];
int main() {
  int n, m, k;
  while (scanf("%d%d%d", &n, &m, &k) != EOF) {
    int i, j;
    for (i = 0; i < n; ++i) scanf("%d", num + i);
    if (n % 2 == 0) {
      printf("0\n");
      continue;
    }
    long long mm = (n + 1) / 2;
    mm = m / mm;
    mm *= k;
    int maxx = 2000000000;
    for (i = 0; i < n; i += 2) maxx = min(num[i], maxx);
    if (maxx > mm)
      cout << mm << endl;
    else
      cout << maxx << endl;
  }
}
