#include <bits/stdc++.h>
using namespace std;
long long n, d, a[100010], i, ans, b;
int main() {
  scanf("%d%d%d", &n, &d, &b);
  for (i = 1; i <= n; i++) scanf("%d", &a[i]), a[i] += a[i - 1];
  for (i = 1; i <= n + 1 >> 1; i++)
    ans = max(ans, max(i - a[min(n, 1ll * i * (d + 1))] / b,
                       i - (a[n] - a[max(0ll, n - 1ll * i * (d + 1))]) / b));
  printf("%d\n", ans);
}
