578_C. Weakness and Poorness
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.
```python
""" Python 3 compatibility tools. """
from __future__ import division, print_function
import itertools
import sys
import os
from io import BytesIO, IOBase


if sys.version_info[0] < 3:
  input = raw_input
  range = xrange

  filter = itertools.ifilter
  map = itertools.imap
  zip = itertools.izip


def is_it_local():
  script_dir = str(os.getcwd()).split('/')
  username = "dipta007"
  return username in script_dir


def READ(fileName):
  if is_it_local():
    sys.stdin = open(f'./{fileName}', 'r')

# region fastio
BUFSIZE = 8192

class FastIO(IOBase):
  newlines = 0

  def __init__(self, file):
    self._fd = file.fileno()
    self.buffer = BytesIO()
    self.writable = "x" in file.mode or "r" not in file.mode
    self.write = self.buffer.write if self.writable else None

  def read(self):
    while True:
      b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
      if not b:
          break
      ptr = self.buffer.tell()
      self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
    self.newlines = 0
    return self.buffer.read()

  def readline(self):
    while self.newlines == 0:
      b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
      self.newlines = b.count(b"\n") + (not b)
      ptr = self.buffer.tell()
      self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
    self.newlines -= 1
    return self.buffer.readline()

  def flush(self):
    if self.writable:
      os.write(self._fd, self.buffer.getvalue())
      self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
  def __init__(self, file):
    self.buffer = FastIO(file)
    self.flush = self.buffer.flush
    self.writable = self.buffer.writable
    self.write = lambda s: self.buffer.write(s.encode("ascii"))
    self.read = lambda: self.buffer.read().decode("ascii")
    self.readline = lambda: self.buffer.readline().decode("ascii")

if not is_it_local():
  sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  input = lambda: sys.stdin.readline().rstrip("\r\n")

# endregion


def input1(type=int):
  return type(input())


def input2(type=int):
  [a, b] = list(map(type, input().split()))
  return a, b


def input3(type=int):
  [a, b, c] = list(map(type, input().split()))
  return a, b, c


def input_array(type=int):
  return list(map(type, input().split()))


def input_string():
  s = input()
  return list(s)

if is_it_local():
  def debug(*args):
    st = ""
    for arg in args:
      st += f"{arg} "
    print(st)
else:
  def debug(*args):
    pass

##############################################################

arr = []

def fun(x):
  cum = 0
  res = 0
  for v in arr:
    nw = (v-x)
    cum += nw
    cum = max(cum, 0)
    res = max(res, cum)
    # print(v, nw, cum, res)
  
  cum = 0
  for v in arr:
    nw = -(v-x)
    cum += nw
    cum = max(cum, 0)
    res = max(res, cum)
    # print(v, nw, cum, res)
  
  return res

def main():
  global arr
  n = input1()
  arr = input_array()

  low = -10000
  high = 10000
  loop = 100
  # print(fun(2.0))
  # return
  while loop > 0:
    loop -= 1

    m1 = ( low * 2.0 + high ) / 3.0
    m2 = ( low + high * 2.0) / 3.0
    y1 = fun(m1)
    y2 = fun(m2)

    # print(y1, y2)

    if y1 > y2:
      low = m1
    else:
      high = m2
  
  # print("res", low, high, (low + high) / 2.0)
  print(fun((low + high) / 2.0))
  pass

if __name__ == '__main__':
  # READ('in.txt')
  main()
```