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 = 3e-12;
int n;
double a[200005], b[200005];
double maxsum() {
  double ans = 0, tmp = 0;
  for (int i = 1; i <= n; i++) {
    tmp += b[i];
    if (tmp < 0) tmp = 0;
    ans = max(tmp, ans);
  }
  return ans;
}
double cal(double x) {
  for (int i = 1; i <= n; i++) b[i] = a[i] - x;
  double ans1 = maxsum();
  for (int i = 1; i <= n; i++) b[i] = -b[i];
  double ans2 = maxsum();
  return max(ans1, ans2);
}
int main() {
  while (scanf("%d", &n) != EOF) {
    for (int i = 1; i <= n; i++) scanf("%lf", &a[i]);
    double l = -10005, r = 10005;
    while (r - l > eps) {
      double m1 = l + (r - l) / 3.0;
      double m2 = r - (r - l) / 3.0;
      if (cal(m1) < cal(m2))
        r = m2;
      else
        l = m1;
    }
    printf("%.15f\n", cal(l));
  }
  return 0;
}