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;
int a[200009], n, times = 200;
double cal(double x) {
  double s_max = 0, s_min = 0, t_max = 0, t_min = 0;
  for (int i = 1; i <= n; i++) {
    t_max += (a[i] - x);
    t_min += (a[i] - x);
    s_max = max(s_max, t_max);
    s_min = min(s_min, t_min);
    if (t_max < 0) t_max = 0;
    if (t_min > 0) t_min = 0;
  }
  return max(s_max, -s_min);
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  double l = -1e9, r = 1e9, mid, x, le, ri;
  while (times--) {
    le = l + (r - l) / 3;
    ri = r - (r - l) / 3;
    if (cal(ri) > cal(le))
      r = ri;
    else
      l = le;
  }
  printf("%.10f\n", cal(l));
}