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 int MX = 2e5 + 5;
int A[MX], n;
double f(double x) {
  double s1 = A[1] - x, s2 = A[1] - x;
  double Max = s1, Min = s2;
  for (int i = 2; i <= n; i++) {
    s1 = s1 >= 0 ? s1 + A[i] - x : A[i] - x;
    s2 = s2 <= 0 ? s2 + A[i] - x : A[i] - x;
    Max = max(Max, s1);
    Min = min(Min, s2);
  }
  return max(fabs(Max), fabs(Min));
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &A[i]);
  }
  double l = -1e4, r = 1e4, m, mm;
  for (int i = 1; i <= 100; i++) {
    m = (l + r) / 2;
    mm = (m + r) / 2;
    if (f(m) <= f(mm))
      r = mm;
    else
      l = m;
  }
  printf("%.8lf\n", f(l));
  return 0;
}