#include <bits/stdc++.h>
using namespace std;
const int N = 200005;
long long n, d, a[N], i, ans, b;
int main() {
  scanf("%I64d%I64d%I64d", &n, &d, &b);
  for (i = 1; i <= n; i++) scanf("%I64d", &a[i]), a[i] += a[i - 1];
  for (i = 1; i <= n + 1 >> 1; i++)
    ans = max(ans, max(i - a[min(n, i * (d + 1))] / b,
                       i - (a[n] - a[max(0ll, n - i * (d + 1))]) / b));
  printf("%I64d\n", ans);
}
