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;
const double eps = 1e-11;
int n;
int a[200010];
double b[200010];
double l = -20000, r = 20000, ans = 2147483647, w1, w2, v1, v2;
double make(double x) {
  double maxh = -2147483647, tmp = 0, minh = 2147483647;
  for (int i = 1; i <= n; i++) b[i] = a[i] - x;
  for (int i = 1; i <= n; i++) {
    if (tmp < 0)
      tmp = b[i];
    else
      tmp += b[i];
    if (tmp > maxh) maxh = tmp;
  }
  tmp = 0;
  for (int i = 1; i <= n; i++) {
    if (tmp > 0)
      tmp = b[i];
    else
      tmp += b[i];
    if (tmp < minh) minh = tmp;
  }
  return max(maxh, -minh);
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  for (int i = 1; i <= 200; i++) {
    w1 = l + (r - l) / 3;
    w2 = r - (r - l) / 3;
    v1 = make(w1);
    v2 = make(w2);
    if (v1 < v2)
      r = w2, ans = min(ans, v1);
    else
      l = w1, ans = min(ans, v2);
  }
  printf("%.15lf", ans);
  return 0;
}