#include <bits/stdc++.h>
using namespace std;
int num[100005];
int lsum[100005], rsum[100005];
int main() {
  int n, b, d;
  int nowl, nowr, ansl, ansr;
  nowl = nowr = ansl = ansr = 0;
  scanf("%d%d%d", &n, &d, &b);
  for (int i = 1; i <= n; i++) scanf("%d", &num[i]);
  for (int i = 1; i <= n; i++) lsum[i] = lsum[i - 1] + num[i];
  for (int i = n; i > 0; i--) rsum[i] = rsum[i + 1] + num[i];
  for (int i = 1; i <= (n + 1) / 2; i++) {
    if (lsum[min(i + 1LL * i * d, 1LL * n)] >= (nowl + 1) * b)
      nowl++;
    else
      ansl++;
    if (i <= n - i) {
      if (rsum[max(1LL, n - i + 1 - 1LL * i * d)] >= (nowr + 1) * b)
        nowr++;
      else
        ansr++;
    }
  }
  printf("%d\n", max(ansl, ansr));
  return 0;
}
