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;
void RI() {}
template <typename... T>
void RI(int &head, T &...tail) {
  scanf("%d", &head);
  RI(tail...);
}
const int N = 2e5 + 10;
double mcs(int n, double a[N]) {
  double mx = 0, now = 0;
  for (int i = 0; i < int(n); i++) {
    now += a[i];
    if (now > mx) mx = now;
    if (now < 0) now = 0;
  }
  return mx;
}
int n, a[N];
double b[N];
void calc(double m, double &vp, double &vn) {
  for (int i = 0; i < int(n); i++) b[i] = a[i] - m;
  vp = mcs(n, b);
  for (int i = 0; i < int(n); i++) b[i] *= -1;
  vn = mcs(n, b);
}
int main() {
  RI(n);
  for (int i = 0; i < int(n); i++) RI(a[i]);
  double l = *min_element(a, a + n);
  double r = *max_element(a, a + n);
  for (int t = 0; t < int(100); t++) {
    double m = (l + r) / 2, vp, vn;
    calc(m, vp, vn);
    if (vp > vn)
      l = m;
    else
      r = m;
  }
  double m = (l + r) / 2, vp, vn;
  calc(m, vp, vn);
  printf("%.12f\n", max(vp, vn));
  return 0;
}