#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 7;
const long long mod = 1e9 + 7;
int n, m, d, b;
long long a[maxn] = {0};
long long sum(long long l, long long r) {
  if (l < 1) l = 1;
  if (r > n) r = n;
  return (a[r] - a[l - 1]);
}
int main() {
  cin >> n >> d >> b;
  for (int i = 1; i <= n; ++i) {
    scanf("%I64d", &a[i]);
    a[i] += a[i - 1];
  }
  m = n / 2;
  int cnt1 = 0, cnt2 = 0;
  for (int i = 1; i <= m; ++i) {
    if (sum(1, i + (long long)i * d) >= (long long)(cnt1 + 1) * b) cnt1++;
    if (sum(n - i + 1 - (long long)i * d, n) >= (long long)(cnt2 + 1) * b)
      cnt2++;
  }
  cout << max(m - cnt1, m - cnt2) << endl;
  return 0;
}
