#include <bits/stdc++.h>
using namespace std;
const int N = 100000 + 9;
const int Mod = 1000000007;
long long n, d, b;
long long a[N];
int main() {
  cin >> n >> d >> b;
  for (int i = 1; i <= n; i++) {
    scanf("%I64d", &a[i]);
  }
  for (int i = 1; i <= n; i++) a[i] = a[i - 1] + a[i];
  long long L = 0, R = 0, Lans = 0, Rans = 0;
  for (int i = 1; i <= (n + 1) / 2; i++) {
    if (a[min(n, (d + 1) * i)] >= (L + 1) * b)
      L++;
    else
      Lans++;
  }
  for (int i = n; i > n - (n + 1) / 2; i--) {
    if (a[n] - a[max(0ll, i - (n - i + 1) * d - 1)] >= (R + 1) * b)
      R++;
    else
      Rans++;
  }
  cout << max(Lans, Rans) << endl;
}
