#include <bits/stdc++.h>
long long k, L, R, a[2222222], b[2222222], ans, sum[2222222];
int n, r;
long long min(long long a, long long b) { return a < b ? a : b; }
long long max(long long a, long long b) { return a > b ? a : b; }
bool check(long long x) {
  long long ans = 0, now = 0;
  memset(b, 0, sizeof(b));
  for (int i = 1; i <= n; i++) {
    now += b[i];
    if (a[i] + now < x)
      ans += x - a[i] - now, b[i + 2 * r + 1] -= x - a[i] - now,
          now += x - a[i] - now;
    if (ans > k) return 0;
  }
  return 1;
}
int main() {
  scanf("%d%d%lld", &n, &r, &k);
  L = 2e18;
  for (int i = 1; i <= n; i++)
    scanf("%lld", &sum[i]), L = min(L, sum[i]), sum[i] += sum[i - 1];
  for (int i = 1; i <= n; i++)
    a[i] = sum[min(i + r, n)] - sum[max(0, i - r - 1)];
  R = 1e20;
  while (L <= R) {
    long long mid = L + R >> 1;
    if (check(mid))
      L = mid + 1, ans = mid;
    else
      R = mid - 1;
  }
  printf("%lld\n", ans);
}
