Problem: You are given a sequence of n integers a1, a2, ..., an. 

Determine a real number x such that the weakness of the sequence a1 - x, a2 - x, ..., an - x is as small as possible.

The weakness of a sequence is defined as the maximum value of the poorness over all segments (contiguous subsequences) of a sequence.

The poorness of a segment is defined as the absolute value of sum of the elements of segment.

Input

The first line contains one integer n (1 ≤ n ≤ 200 000), the length of a sequence.

The second line contains n integers a1, a2, ..., an (|ai| ≤ 10 000).

Output

Output a real number denoting the minimum possible weakness of a1 - x, a2 - x, ..., an - x. Your answer will be considered correct if its relative or absolute error doesn't exceed 10 - 6.

Examples

Input

3
1 2 3


Output

1.000000000000000


Input

4
1 2 3 4


Output

2.000000000000000


Input

10
1 10 2 9 3 8 4 7 5 6


Output

4.500000000000000

Note

For the first case, the optimal value of x is 2 so the sequence becomes  - 1, 0, 1 and the max poorness occurs at the segment "-1" or segment "1". The poorness value (answer) equals to 1 in this case. 

For the second sample the optimal value of x is 2.5 so the sequence becomes  - 1.5, - 0.5, 0.5, 1.5 and the max poorness occurs on segment "-1.5 -0.5" or "0.5 1.5". The poorness value (answer) equals to 2 in this case.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
double a[1234567], b[200030];
int n;
double fun() {
  int i;
  double maxend = 0.0000, maxsofar = 0.000000;
  for (i = 0; i < n; i++) {
    maxend = max(b[i], maxend + b[i]);
    maxsofar = max(maxsofar, maxend);
  }
  return maxsofar;
}
int main() {
  cin >> n;
  int i;
  for (i = 0; i < n; i++) cin >> a[i];
  double lo = -1e9, hi = 1e9, m1, m2;
  int t = 100;
  while (t--) {
    double mid = (lo + hi) / 2;
    for (i = 0; i < n; i++) b[i] = a[i] - mid;
    m1 = fun();
    for (i = 0; i < n; i++) b[i] = b[i] * (-1);
    m2 = fun();
    if (m1 > m2)
      lo = mid;
    else
      hi = mid;
  }
  printf("%.12lf\n", max(m1, m2));
  return 0;
}