#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 5;
long long a[MAXN], sum[MAXN], n, d, b;
int main() {
  scanf("%lld%lld%lld", &n, &d, &b);
  for (int i = 1; i <= n; i++) {
    scanf("%lld", &a[i]);
    sum[i] = sum[i - 1] + a[i];
  }
  long long numl = 0, numr = 0;
  for (int i = 1; i <= (n + 1) / 2; i++)
    if (sum[min(n, 1ll * i * d + i)] - numl * b >= b) numl++;
  for (int i = n; i > (n + 1) / 2; i--)
    if (sum[n] - sum[max(0ll, n - 1ll * (n - i + 1) * d - (n - i + 1))] -
            numr * b >=
        b)
      numr++;
  printf("%lld", max((n + 1) / 2 - numl, n / 2 - numr));
}
