#include <bits/stdc++.h>
using namespace std;
long long n, d, b, a[100500], sum[100500], x1, x2, x;
int main() {
  scanf("%lld%lld%lld", &n, &d, &b);
  for (long long i = 1; i <= n; i++) {
    scanf("%lld", &a[i]);
    sum[i] = sum[i - 1] + a[i];
  }
  for (long long i = 1; i <= n >> 1; i++) {
    x = sum[min(n, i * (d + 1))] - b * x1;
    if (x >= b) x1++;
    x = sum[n] - sum[max(0ll, n - i * (d + 1))] - b * x2;
    if (x >= b) x2++;
  }
  printf("%lld", (n >> 1) - min(x1, x2));
  return 0;
}
