#include <bits/stdc++.h>
using namespace std;
long long read() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
const long long N = 2e5 + 50;
long long n, m, D, B, ans = 0;
long long a[N], s[N];
int main() {
  long long i, p, now, val;
  n = read();
  D = read();
  B = read();
  m = (n + 1) >> 1;
  for (i = 1; i <= n; i++) {
    a[i] = read();
    s[i] = s[i - 1] + a[i];
  }
  now = val = 0;
  for (i = 1; i <= m; i++) {
    p = min(i * (D + 1), n);
    if (s[p] - now >= B) val++, now += B;
  }
  ans = max(ans, m - val);
  now = val = 0;
  for (i = n; i > m; i--) {
    p = max(n - (n - i + 1) * (D + 1) + 1, 1ll);
    if (n * B - s[p - 1] - now >= B) val++, now += B;
  }
  ans = max(ans, n - m - val);
  printf("%lld", ans);
  return 0;
}
