#include <bits/stdc++.h>
using namespace std;
const long long N = 100010;
long long n, b, d, a[N], s[N];
signed main() {
  scanf("%lld%lld%lld", &n, &d, &b);
  for (long long i = 1; i <= n; i++)
    scanf("%lld", &a[i]), s[i] = s[i - 1] + a[i];
  long long cnt1 = 0, cnt2 = 0, sum;
  for (long long i = 1; i <= n / 2; i++) {
    sum = s[min(n, i * (d + 1))] - cnt1 * b;
    if (sum >= b) cnt1++;
    sum = s[n] - s[max(0ll, n - i * (1 + d))] - cnt2 * b;
    if (sum >= b) cnt2++;
  }
  printf("%lld\n", n / 2 - min(cnt1, cnt2));
  return 0;
}
