#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const long long LLinf = 0x3f3f3f3f3f3f3f3f;
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 * 10ll + ch - '0';
    ch = getchar();
  }
  return x * f;
}
const int maxn = 200000 + 10;
long long n, d, b;
long long s[maxn];
long long ans1, ans2;
long long query(long long l, long long r) {
  if (r > n) r = n;
  if (l < 1) l = 1;
  return s[r] - s[l - 1];
}
void build() {
  n = read();
  d = read();
  b = read();
  for (int i = 1, a; i <= n; i++) {
    a = read();
    s[i] = a + s[i - 1];
  }
}
void solve() {
  for (int i = 1; i <= n / 2; i++) {
    if (query(1, i + i * d) >= (ans1 + 1) * b) ans1++;
    if (query(n - i + 1 - i * d, n) >= (ans2 + 1) * b) ans2++;
  }
  cout << max(n / 2 - ans1, n / 2 - ans2) << '\n';
}
int main() {
  build();
  solve();
  return 0;
}
