#include <bits/stdc++.h>
using namespace std;
long long arr[10000];
long long N, M, K;
int main() {
  scanf("%I64d", &N);
  ;
  scanf("%I64d", &M);
  ;
  scanf("%I64d", &K);
  ;
  for (int(n) = 0; n < (int)N; n++) {
    scanf("%I64d", &arr[n]);
    ;
  }
  if (N == 1) {
    long long sol = 0;
    while (arr[0] > 0 && K > 0) {
      sol += min(arr[0], M);
      arr[0] -= min(arr[0], M);
      K--;
    }
    printf("%I64d\n", sol);
  } else if (N % 2 == 0) {
    puts("0");
  } else {
    long long MIN = arr[0];
    int len = 0;
    for (int n = 0; n < N; n += 2) {
      len++;
      MIN = min(arr[n], MIN);
    }
    M = M / len;
    printf("%I64d\n", min(K * M, MIN));
  }
}
