10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

#include <bits/stdc++.h>
using namespace std;
int n;
double a[2200000];
int main() {
  cin >> n;
  double suma = 0.0;
  for (int i = (int)1; i <= (int)n; i++) {
    cin >> a[i];
    suma += a[i];
  }
  double k = suma / (double)n;
  for (int i = (int)1; i <= (int)n; i++) {
    a[i] -= k;
  }
  double sum = 0.0, pre = 0.0;
  double ans = 0.0;
  for (int i = 1; i <= n; i++) {
    pre = sum;
    sum += a[i];
    if (fabs(sum) < fabs(pre)) {
      if (ans + 1e-4 < fabs(pre)) {
        ans = fabs(pre);
      }
    }
  }
  printf("%15lf\n", ans);
  return 0;
}
