You have final scores of an examination for n students. Calculate standard deviation of the scores s1, s2 ... sn.

The variance α2 is defined by

α2 = (∑ni=1(si - m)2)/n

where m is an average of si. The standard deviation of the scores is the square root of their variance.

Constraints

* n ≤ 1000
* 0 ≤ si ≤ 100

Input

The input consists of multiple datasets. Each dataset is given in the following format:


n
s1 s2 ... sn


The input ends with single zero for n.

Output

For each dataset, print the standard deviation in a line. The output should not contain an absolute error greater than 10-4.

Example

Input

5
70 80 100 90 20
3
80 80 80
0


Output

27.85677655
0.00000000

Source: aizu | Difficulty: UNKNOWN_DIFFICULTY


Solutions:
import math
n = int(input())
while not n == 0:
	ss = [float(i) for i in input().split(' ')]
	m = sum(ss) / n
	a2 = sum([(i - m) ** 2 for i in ss]) / n
	print(math.sqrt(a2))
	n = int(input())


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	ss = list(((si - m) ** 2 for si in s))
	S = sum(ss) / n
	print(S ** 0.5)


while 1:
	n = int(input())
	if n == 0:
		break
	lst = list(map(int, input().split()))
	ave = sum(lst) / n
	sigma = sum([(x - ave) ** 2 for x in lst]) / n
	print(sigma ** 0.5)


while True:
	n = int(input())
	import statistics
	if n == 0:
		break
	s = list(map(int, input().split()))
	a = float('{:.6f}'.format(statistics.pstdev(s)))
	print(a)


from statistics import pstdev
while True:
	n = int(input())
	if not n:
		break
	s = list(map(int, input().split()))
	print(pstdev(s))


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	stdnt = list(map(int, input().split()))
	std = statistics.pstdev(stdnt)
	print(std)


from statistics import pstdev
for _ in range(1000):
	n = int(input())
	if n == 0:
		break
	arg = list(map(int, input().split()))
	print(pstdev(arg))


import statistics
while True:
	if int(input()) == 0:
		break
	print('%.8f' % statistics.pstdev(list(map(int, input().split()))))


while 1:
	N = int(input())
	if not N:
		break
	(*A,) = map(int, input().split())
	V = sum(A) / N
	print((sum(((a - V) ** 2 for a in A)) / N) ** 0.5)


import statistics
while 1:
	n = int(input())
	if n == 0:
		exit()
	s = [int(i) for i in input().split()]
	print(statistics.pstdev(s))


while int(input()):
	score = list(map(int, input().split()))
	M = sum(score) / len(score)
	SD = (sum([(n - M) ** 2 for n in score]) / len(score)) ** 0.5
	print('{:.4f}'.format(SD))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	x = 0
	for i in range(n):
		x += (s[i] - m) ** 2
	a = x / n
	print(math.sqrt(a))


import math
while int(input()):
	x = [float(k) for k in input().split()]
	n = len(x)
	m = sum(x) / n
	print(math.sqrt(sum([(t - m) ** 2 for t in x]) / n))


while 1:
	if input() == '0':
		break
	s = list(map(int, input().split()))
	m = sum(s) / len(s)
	m_2 = sum((i ** 2 for i in s)) / len(s)
	print('{0:f}'.format((m_2 - m ** 2) ** 0.5))


while True:
	n = int(input())
	if n == 0:
		exit()
	(*a,) = map(int, input().split())
	m = sum(a) / len(a)
	s = (sum([(m - ai) ** 2 for ai in a]) / len(a)) ** 0.5
	print(s)


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	li = [int(x) for x in list(input().split())]
	stdev = statistics.pstdev(li)
	print(round(stdev, 8))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	print(math.sqrt(sum([(x - sum(s) / n) ** 2 for x in s]) / n))


import statistics
import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	A = statistics.pstdev(s)
	print(A)


import statistics, math
while True:
	N = int(input())
	if N == 0:
		break
	s = list(map(int, input().split()))
	pstdev = statistics.pstdev(s)
	print(pstdev)


import statistics
while True:
	if int(input()) != 0:
		arr = list(map(float, input().split()))
		print(statistics.pstdev(arr))
	else:
		break


from statistics import pstdev
while input() != '0':
	s = list(map(int, input().split()))
	print(pstdev(s))


import statistics as st
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	print(f'{st.pstdev(s):.5f}')


from statistics import pstdev
while True:
	n = input()
	if n == '0':
		break
	print(pstdev(list(map(int, input().split()))))


from math import *
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	s2 = 0
	for i in s:
		s2 += (i - m) ** 2
	print(sqrt(s2 / n))


while True:
	N = int(input())
	if N == 0:
		break
	S = list(map(float, input().split()))
	avg = sum(S) / N
	bunsan = 0
	for s in S:
		bunsan += (s - avg) ** 2
	bunsan /= N
	print(bunsan ** 0.5)


import statistics
while 1:
	n = int(input())
	if n == 0:
		break
	else:
		data = list(map(int, input().split()))
		print(statistics.pstdev(data))


from statistics import pstdev
while True:
	if input() == '0':
		break
	print(pstdev([int(i) for i in input().split()]))


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	str = input().split()
	list = []
	for i in range(n):
		list.append(int(str[i]))
	print(statistics.pstdev(list))


import math
while 1:
	a = 0
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / len(s)
	for i in range(n):
		a = a + pow(s[i] - m, 2)
	print(math.sqrt(a / n))


while 1:
	n = int(input())
	if n == 0:
		break
	L = list(map(int, input().split()))
	mean = sum(L) / len(L)
	V = sum(((s - mean) ** 2 for s in L)) / len(L)
	print(V ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = tuple(map(int, input().split()))
	su = sum(s)
	m = sum(s) / n
	print(math.sqrt(sum([(si - m) ** 2 for si in s]) / float(n)))


import math
while True:
	N = int(input())
	if N == 0:
		break
	S = list(map(int, input().split()))
	S2 = [x ** 2 for x in S]
	V = sum(S2) / N - (sum(S) / N) ** 2
	print(math.sqrt(V))


import math
while True:
	n = int(input())
	if n == 0:
		break
	p = list(map(int, input().split()))
	m = sum(p) / n
	h = 0
	for i in range(n):
		h += (p[i] - m) ** 2
	print(math.sqrt(h / n))


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a = 0
	for si in s:
		a += (si - m) ** 2
	b = (a / n) ** 0.5
	print('{:.5f}'.format(b))


while True:
	n = int(input())
	if n == 0:
		break
	a = list(map(int, input().split()))
	mean = sum(a) / n
	std = 0
	for i in range(n):
		std += (a[i] - mean) ** 2
	std /= n
	print(std ** 0.5)


while True:
	a = int(input())
	if a == 0:
		break
	b = list(map(float, input().split()))
	m = sum(b) / a
	ver = 0.0
	for i in b:
		ver += (i - m) ** 2 / a
		s = ver ** 0.5
	print(s)


from statistics import pstdev
while True:
	data_count = int(input())
	if data_count == 0:
		break
	print(pstdev(map(int, input().split())))


while input() != '0':
	n = list(map(int, input().split()))
	b = len(n)
	m = sum(n) / b
	print((sum(((x - m) ** 2 for x in n)) / b) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	sd = (sum(list(map(lambda x: (x - m) ** 2, s))) / n) ** 0.5
	print(sd)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = [float(s) for s in input().split()]
	m = sum(s) / n
	a2 = [(d - m) ** 2 for d in s]
	print(math.sqrt(sum(a2) / n))


import math
while True:
	n = int(input())
	if n == 0:
		break
	i = list(map(int, input().split(' ')))
	avg = sum(i) / n
	j = list(map(lambda x: (x - avg) ** 2, i))
	print('{:.5f}'.format(math.sqrt(sum(j) / n)))


from statistics import pstdev
while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	print(pstdev(s))


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a2 = sum([(s[i] - m) ** 2 for i in range(n)]) / n
	a = a2 ** 0.5
	print(a)


from statistics import pstdev
while True:
	n = int(input())
	if n == 0:
		break
	l = list(map(int, input().split()))
	print(pstdev(l))


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	m = sum(s) / n
	a = (sum(((s[i] - m) ** 2 for i in range(n))) / n) ** 0.5
	print(a)


from statistics import pstdev
while input() != '0':
	s = list(map(int, input().split()))
	print('{:.8f}'.format(pstdev(s)))


import statistics
import sys
data_sets = sys.stdin.read().split('\n')
for i in data_sets[1:-1:2]:
	data_set = [int(j) for j in i.split()]
	print(statistics.pstdev(data_set))


import statistics
while True:
	x = int(input())
	if x == 0:
		break
	else:
		ls = list(map(int, input().split()))
		print('{0:.8f}'.format(statistics.pstdev(ls)))


import math
while True:
	n = int(input())
	if n == 0:
		break
	score = list(map(int, input().split()))
	m = sum(score) / n
	s = 0
	for i in range(n):
		s += pow(score[i] - m, 2)
	print(str(math.sqrt(s / n)))


while True:
	n = int(input())
	if n <= 0:
		break
	s = [int(x) for x in input().split()]
	m = sum(s) / n
	s = [(x - m) ** 2 for x in s]
	print('%.8f' % (sum(s) / n) ** 0.5)


import statistics
while True:
	a = int(input())
	num = []
	if a == 0:
		break
	else:
		num = list(map(int, input().split()))
	print(statistics.pstdev(num))


from statistics import pstdev
while True:
	n = input()
	if n == '0':
		break
	print(pstdev(map(int, input().split())))


while 1:
	n = int(input())
	if n == 0:
		break
	a = list(map(int, input().split()))
	a2 = [(i - sum(a) / n) ** 2 for i in a]
	print((sum(a2) / n) ** 0.5)


while input() != '0':
	n_std = float(0)
	n_l = list(map(int, input().split()))
	n_av = sum(n_l) / len(n_l)
	for i in n_l:
		n_std += (i - n_av) ** 2
	n_std = (n_std / len(n_l)) ** 0.5
	print(f'{n_std:.6f}')


import statistics
while 1:
	n = input()
	if n == '0':
		break
	a = [int(i) for i in input().split()]
	print(statistics.pstdev(a))


while input() != '0':
	n = list(map(int, input().split()))
	b = len(n)
	a = sum(n) / b
	c = (sum(((x - a) ** 2 for x in n)) / b) ** 0.5
	print(c)


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	s = [int(p) for p in input().split()]
	print(statistics.pstdev(s))


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	else:
		data = [float(s) for s in input().split()]
		print(statistics.pstdev(data))


import statistics
data = []
while True:
	n = eval(input())
	if n == 0:
		break
	data.append(list(map(int, input().split())))
Data = iter(data)
for i in Data:
	print(statistics.pstdev(i))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / len(s)
	a = math.sqrt(sum(((i - m) ** 2 for i in s)) / len(s))
	print(format(a, '.8f'))


import statistics
ans = []
while True:
	n = int(input())
	if n == 0:
		break
	data = list(map(int, input().split()))
	v = statistics.pstdev(data)
	ans.append(v)
for a in ans:
	print(a)


while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	a = sum(s) / n
	print((sum([x * x for x in s]) / n - a * a) ** 0.5)


while input() != '0':
	l = list(map(int, input().split()))
	print('{0:.8f}'.format((sum([(s - sum(l) / len(l)) ** 2 for s in l]) / len(l)) ** 0.5))


import statistics as st
while True:
	student_n = int(input())
	if student_n == 0:
		break
	score_lst = map(int, input().split())
	print(st.pstdev(score_lst))


import math
n = int(input())
while n:
	s = list(map(float, input().split()))
	m = sum(s) / n
	tmp = 0
	for si in s:
		tmp += (si - m) ** 2
	print(math.sqrt(tmp / n))
	n = int(input())


while input() != '0':
	n = list(map(int, input().split()))
	b = len(n)
	a = sum(n) / b
	print((sum(((x - a) ** 2 for x in n)) / b) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	scores = list(map(int, input().split()))
	mean = sum(scores) / n
	print((sum([(score - mean) ** 2 for score in scores]) / n) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s = [float(x) for x in input().split()]
	m = sum(s) / n
	a = (sum([(x - m) ** 2 for x in s]) / n) ** 0.5
	print(a)


while True:
	n = int(input())
	if n == 0:
		break
	a = [float(i) for i in input().split()]
	average = sum(a) / n
	print((sum([(i - average) ** 2 for i in a]) / n) ** 0.5)


ans = list()
while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	avg = sum(s) / n
	tmp = 0
	for i in s:
		tmp += (i - avg) ** 2
	ans += [(tmp / n) ** (1 / 2)]
for i in ans:
	print(i)


while True:
	n = int(input())
	if n == 0:
		break
	l = list(map(int, input().split()))
	m = sum(l) / n
	print(f'{(sum(((s - m) ** 2 for s in l)) / n) ** 0.5:.5f}')


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	print((sum(map(lambda x: x * x, s)) / n - (sum(s) / n) ** 2) ** 0.5)


from statistics import pstdev
while True:
	if input() == '0':
		break
	v_list = (int(x) for x in input().split())
	print(pstdev(v_list))


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	s = map(float, input().split())
	print(statistics.pstdev(s))


for i in range(10 ** 6):
	n = int(input())
	if n == 0:
		break
	L = list(map(int, input().split()))
	Ave = sum(L) / n
	CV = 0
	for j in range(n):
		CV += (L[j] - Ave) ** 2
	print((CV / n) ** 0.5)


while input() != '0':
	v = list(map(int, input().split()))
	m = sum(v) / len(v)
	sum_sq = 0
	for i in range(len(v)):
		sum_sq = (v[i] - m) ** 2 + sum_sq
	print((sum_sq / len(v)) ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = [int(_) for _ in input().split()]
	m = sum(s) / n
	a = math.sqrt(sum([pow(_ - m, 2) for _ in s]) / n)
	print(a)


while True:
	n = int(input())
	if n == 0:
		break
	a = list(map(int, input().split()))
	m = sum(a) / n
	func = lambda x: (x - m) ** 2
	print((sum(map(func, a)) / n) ** 0.5)


while True:
	import math
	n = int(input())
	if n == 0:
		break
	st = list(map(int, input().split()))
	hei = sum(st) / n
	hensa = []
	for a in range(n):
		hensa.append((st[a] - hei) ** 2 / n)
	print(math.sqrt(sum(hensa)))


import statistics
import math
while True:
	n = int(input())
	if n == 0:
		break
	d = list(map(int, input().split()))
	pstdev = statistics.pstdev(d)
	print(pstdev)


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	s = tuple(map(int, input().split()))
	print(f'{statistics.pstdev(s):.5f}')


from statistics import pstdev
while True:
	n = int(input())
	if n == 0:
		break
	else:
		S = list(map(float, input().split()))
		print(pstdev(S))


while 1:
	n = int(input())
	if n == 0:
		break
	box = list(map(float, input().split()))
	mean = sum(box) / n
	for i in range(n):
		box[i] = (box[i] - mean) ** 2
	print('%.10f' % (sum(box) / n) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s_list = list(map(int, input().split()))
	m = float(sum(s_list) / len(s_list))
	print((sum([(s - m) ** 2 for s in s_list]) / n) ** 0.5)


while input() != '0':
	s = list(map(int, input().split()))
	n = len(s)
	m = sum(s) / n
	a = (sum(((x - m) ** 2 for x in s)) / n) ** 0.5
	print(a)


import statistics
while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	sd = statistics.pstdev(s)
	print(sd)


from statistics import pstdev

def main():
	while int(input()) != 0:
		scores = map(float, input().split())
		print('{:.5f}'.format(pstdev(scores)))
main()


import statistics
while input() != '0':
	print('{0:.6f}'.format(statistics.pstdev(map(float, input().split()))))


while True:
	n = int(input())
	if n == 0:
		break
	A = list(map(int, input().split()))
	m = sum(A) / n
	N = (sum(((a - m) ** 2 for a in A)) / n) ** 0.5
	print(f'{N:.8f}')


from statistics import *
while int(input()):
	print(pstdev(map(int, input().split())))


while 1:
	n = int(input())
	if n == 0:
		break
	s = [float(i) for i in input().split()]
	m = sum(s) / n
	a = (sum([(i - m) ** 2 for i in s]) / n) ** 0.5
	print('{:.8f}'.format(a))


while True:
	N = int(input())
	if N == 0:
		break
	(*A,) = map(int, input().split())
	V = sum(A) / N
	print((sum(((a - V) ** 2 for a in A)) / N) ** 0.5)


while input() != '0':
	l = list(map(float, input().split()))
	m = sum(l) / len(l)
	s = 0
	for i in range(len(l)):
		s += (l[i] - m) ** 2
	print('%.8f' % (s / len(l)) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	scr = list(map(int, input().split()))
	avg = sum(scr) / n
	v = 0
	for scri in scr:
		v += (scri - avg) ** 2 / n
	a = v ** 0.5
	print(a)


import math
n = int(input())
while n != 0:
	sums = 0.0
	s = list(map(float, input().split()))
	m = sum(s) / n
	for i in range(n):
		sums += (s[i] - m) ** 2 / n
	print(math.sqrt(sums))
	n = int(input())


import math
for d in iter(input, '0'):
	(n, s) = (int(d), list(map(int, input().split())))
	print(math.sqrt(sum([si ** 2 for si in s]) / n - (sum(s) / n) ** 2))


while True:
	N = int(input())
	if N == 0:
		break
	S = [int(n) for n in input().split()]
	M = sum(S) / len(S)
	a = sum([(s - M) ** 2 for s in S]) / len(S)
	print(a ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	m = sum(s) / n
	a_2 = sum([(x - m) ** 2 for x in s]) / n
	print(a_2 ** 0.5)


from statistics import pstdev
while input() != '0':
	lst = map(int, input().split())
	print(pstdev(lst))


while 1:
	n = float(input())
	if n == 0:
		break
	l = list(map(float, input().split()))
	s = sum(l)
	a = s / n
	c = 0
	for i in l:
		c += (i - a) ** 2
	import math
	print(math.sqrt(c / n))


import statistics
while int(input()):
	data = list(map(float, input().split()))
	print(statistics.pstdev(data))


while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	print((sum([(m - sum(s) / n) ** 2 for m in s]) / n) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	scores = list(map(int, input().split()))
	m = sum(scores) / n
	s = 0
	for i in scores:
		s += (i - m) ** 2
	print((s / n) ** 0.5)


while 1:
	n = int(input())
	if n == 0:
		break
	s = [int(x) for x in input().split()]
	print((sum([(m - sum(s) / n) ** 2 for m in s]) / n) ** 0.5)


while 1:
	if int(input()) == 0:
		break
	n = list(map(int, input().split()))
	b = len(n)
	a = sum(n) / b
	print((sum(((x - a) ** 2 for x in n)) / b) ** 0.5)


import statistics
while True:
	num = input()
	if num == '0':
		break
	value = map(int, input().split())
	print(statistics.pstdev(value))


while int(input()):
	s = list(map(int, input().split()))
	n = len(s)
	a = sum(s) / n
	print((sum((x * x for x in s)) / n - a * a) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	m = sum(s) / n
	var = sum([(s[i] - m) ** 2 for i in range(n)]) / n
	print('{:.5f}'.format(var ** 0.5))


import statistics
while True:
	n = input()
	if n == '0':
		break
	print(statistics.pstdev(map(int, input().split())))


import statistics
while True:
	dev = input()
	if dev == '0':
		break
	l = [float(i) for i in input().split()]
	pstdev = statistics.pstdev(l)
	print(pstdev)


while True:
	n = int(input())
	if n == 0:
		break
	a = list(map(int, input().split()))
	m = sum(a) / n
	s = 0
	for i in a:
		s += (i - m) ** 2
	print((s / n) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	score = list(map(int, input().split()))
	ave = sum(score) / n
	print((sum([(i - ave) ** 2 for i in score]) / n) ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	S = [int(i) for i in input().split()]
	m = sum(S) / n
	a2 = sum([(s - m) ** 2 for s in S]) / n
	print(a2 ** 0.5)


import math
import statistics
while 1:
	n = int(input())
	if n == 0:
		break
	data = list(map(int, input().split()))
	print(statistics.pstdev(data))


from statistics import pstdev
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	print(pstdev(s))


import statistics
import sys
data_sets = sys.stdin.read().split('\n')
for i in data_sets[1:-1:2]:
	data_set = map(int, i.split())
	print(statistics.pstdev(data_set))


import math
while True:
	n = int(input())
	if n == 0:
		break
	table = list(map(int, input().split()))
	ave = sum(table) / n
	bun = 0
	for i in range(n):
		s = (table[i] - ave) ** 2
		bun += s
	print(math.sqrt(bun / n))


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	m = sum(s) / n
	v = sum([(x - m) ** 2 for x in s]) / n
	print(v ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	r = 0
	m = sum(s) / n
	for i in range(n):
		r += (s[i] - m) ** 2
	print('{:.8f}'.format((r / n) ** 0.5))


import statistics as st
while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	print(st.pstdev(s))


while True:
	n = int(input())
	if n == 0:
		break
	s = [int(i) for i in input().split()]
	ave = sum(s) / n
	sd = (sum([(i - ave) ** 2 for i in s]) / n) ** (1 / 2)
	print(sd)


import math
n = int(input())
while n:
	s = list(map(int, input().split()))
	m = sum(s) / n
	tmp = 0
	for si in s:
		tmp += (si - m) ** 2
	print(math.sqrt(tmp / n))
	n = int(input())


import statistics as st
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	print(st.pstdev(s))


while True:
	n = int(input())
	if n == 0:
		break
	p = list(map(int, input().split()))
	s = 0
	for i in range(n):
		s += (p[i] - sum(p) / len(p)) ** 2
	print((s / n) ** (1 / 2))
	p.clear()


while True:
	n = int(input())
	if n == 0:
		break
	s = [int(i) for i in input().split()]
	av = sum(s) / len(s)
	var = sum([(i - av) ** 2 for i in s]) / n
	print(var ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	data = list(map(int, input().split()))
	m = sum(data) / n
	print('{:.10f}'.format(math.sqrt(sum(((x - m) ** 2 for x in data)) / n)))


while True:
	n = int(input())
	if n == 0:
		break
	S = list(map(int, input().split()))
	m = sum(S) / n
	D = [(i - m) ** 2 for i in S]
	v = sum(D) / n
	SD = v ** 0.5
	print(SD)


import statistics
S = []
while True:
	n = int(input())
	if n == 0:
		break
	S.append(list(map(int, input().split())))
for a in S:
	print(statistics.pstdev(a))


while True:
	n = int(input())
	if n == 0:
		break
	S = []
	S = list(map(int, input().split()))
	m = sum(S) / n
	a = 0
	for i in range(n):
		a += (S[i] - m) ** 2
	a /= n
	print(a ** 0.5)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a = sum(((x - m) ** 2 for x in s)) / n
	print(a ** 0.5)


import statistics as st
while True:
	N = int(input())
	if N == 0:
		break
	buf = list(map(float, input().split()))
	sd = st.pstdev(buf)
	print('%.8f' % sd)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	ans = 0
	for i in range(n):
		ans += (s[i] - sum(s) / n) ** 2
	ans = (ans / n) ** 0.5
	print(ans)


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	else:
		data_set = [int(i) for i in input().split()]
		print(statistics.pstdev(data_set))


while True:
	n = int(input())
	import statistics
	if n == 0:
		break
	s = list(map(int, input().split()))
	x = float('{:.6f}'.format(statistics.pstdev(s)))
	print(x)


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	print(statistics.pstdev(s))


while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a = (sum([(x - m) ** 2 for x in s]) / n) ** 0.5
	print(a)


from statistics import pstdev
while input() != '0':
	print(pstdev(map(int, input().split())))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a = 0
	for i in range(n):
		a += pow(s[i] - m, 2)
	print(math.sqrt(a / n))


while True:
	n = int(input())
	if n == 0:
		break
	S = list(map(int, input().split()))
	avg = sum(S) / n
	ans = (sum([(avg - i) ** 2 for i in S]) / n) ** 0.5
	print(str(ans))


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / len(s)
	v = 0
	for ele in s:
		v += (ele - m) ** 2 / len(s)
	print(v ** 0.5)


while 1:
	r = 0
	S = 0
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	print(sum([(sum(s) / n - i) ** 2 / n for i in s]) ** 0.5)


while True:
	if input() == '0':
		break
	data = list(map(float, input().split()))
	ave = sum(data) / len(data)
	std_div = (sum([(ave - i) ** 2 for i in data]) / len(data)) ** (1 / 2)
	print(std_div)


from statistics import pstdev
while True:
	n = int(input())
	if not n:
		break
	li = [int(i) for i in input().split()]
	print(pstdev(li))


while 1:
	n = int(input())
	if n == 0:
		break
	s = [int(i) for i in input().split()]
	m = sum(s) / n
	a = (sum([(i - m) ** 2 for i in s]) / n) ** 0.5
	print(a)


while True:
	N = int(input())
	if N == 0:
		break
	scores = list(map(int, input().split()))
	m = sum(scores) / N
	print((sum(((score - m) ** 2 for score in scores)) / N) ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / float(n)
	print('{0:.8f}'.format(math.sqrt(sum([(x - m) ** 2 for x in s]) / n)))


import math
while True:
	n = int(input())
	if n == 0:
		break
	data = list(map(float, input().split()))
	ave = sum(data) / n
	data2 = list(map(lambda x: (x - ave) ** 2, data))
	print((sum(data2) / n) ** 0.5)


while input() != '0':
	s = list(map(int, input().split()))
	n = len(s)
	a = sum(s) / n
	print((sum([x * x for x in s]) / n - a * a) ** 0.5)


while True:
	n = int(input())
	if not n:
		break
	s = [int(i) for i in input().split()]
	m = sum(s) / n
	print((sum([(i - m) ** 2 for i in s]) / n) ** 0.5)


n = int(input())
while n != 0:
	(*s,) = map(int, input().split())
	m = sum(s) / n
	a = 0
	for i in range(n):
		a += (s[i] - m) ** 2 / n
	print('{:.8f}'.format(a ** 0.5))
	n = int(input())


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	t = sum(s)
	a = t / n
	b = sum(map(lambda x: (x - a) ** 2, s))
	print(math.sqrt(b / n))


while True:
	n = int(input())
	if n == 0:
		break
	s = [int(x) for x in input().split()]
	m = sum(s) / n
	a = (sum([(x - m) ** 2 for x in s]) / n) ** 0.5
	print(a)


n = int(input())
while n:
	d = [int(i) for i in input().split()]
	print((sum([(i - sum(d) / n) ** 2 for i in d]) / n) ** 0.5)
	n = int(input())


import statistics
while True:
	x = int(input())
	if x == 0:
		break
	else:
		xlist = input().split()
		xlist = [int(s) for s in xlist]
		print(statistics.pstdev(xlist))


while int(input()):
	s = list(map(int, input().split()))
	n = len(s)
	a = sum(s) / n
	print((sum([x * x for x in s]) / n - a * a) ** 0.5)


import math
while True:
	if input() == '0':
		break
	a = list(map(int, input().split()))
	m = sum(a) / len(a)
	b = 0
	for i in a:
		b += (i - m) ** 2.0
	stddev = math.sqrt(b / len(a))
	print(stddev)


while int(input()) != 0:
	a = [int(i) for i in input().split()]
	a = list(map(lambda x: (x - sum(a) / len(a)) ** 2, a))
	print((sum(a) / len(a)) ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	d = list(map(int, input().strip().split()))
	m = sum(d) / n
	print(math.sqrt(sum(((x - m) ** 2 for x in d)) / n))


import math
while True:
	n = int(input())
	if n == 0:
		break
	l = list(map(int, input().split()))
	s = 0
	for i in l:
		s += (i - sum(l) / n) ** 2
	print('{0:.8f}'.format(math.sqrt(s / n)))


import statistics
while 1:
	N = int(input())
	if N == 0:
		break
	else:
		data = list(map(int, input().split()))
		print(statistics.pstdev(data))


while True:
	n = int(input())
	if n == 0:
		break
	pts = list(map(int, input().split()))
	s = 0
	m = sum(pts) / len(pts)
	for pt in pts:
		s += (pt - m) ** 2
	print((s / len(pts)) ** 0.5)


import statistics
while input() != '0':
	data = list(map(float, input().split()))
	print('{0:.6f}'.format(statistics.pstdev(data)))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	x = 0
	m = sum(s) / n
	for i in s:
		x += (i - m) ** 2
	print(math.sqrt(x / n))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a = 0
	for i in range(n):
		a += (s[i] - m) ** 2
	a = a / n
	print(math.sqrt(a))


from statistics import pstdev
while True:
	data_count = int(input())
	if data_count == 0:
		break
	print(pstdev((int(x) for x in input().split())))


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = [int(i) for i in input().split(' ')]
	m = sum(s) / n
	print('{:.8f}'.format(math.sqrt(sum([(x - m) ** 2 for x in s]) / n)))


while True:
	n = int(input())
	if n == 0:
		break
	a = list(map(int, input().split()))
	m = sum(a) / n
	std = 0
	for i in range(n):
		std += (a[i] - m) ** 2
	std /= n
	print(std ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	d = math.sqrt(sum(((m - i) ** 2 for i in s)) / n)
	print(d)


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	m = sum(s) / n
	a_2 = sum([(x - m) ** 2 for x in s]) / n
	print(a_2 ** 0.5)


while int(input()) != 0:
	m = list(map(int, input().split()))
	mean = sum(m) / len(m)
	std = (sum([(i - mean) ** 2 for i in m]) / len(m)) ** 0.5
	print('{:4f}'.format(std))


while True:
	n = int(input())
	if n == 0:
		break
	x = tuple(map(float, input().strip().split()))
	y = (sum(x) / n) ** 2
	z = sum(map(pow, x, (2 for i in range(n)))) / n
	print((z - y) ** 0.5)


import statistics
while True:
	order_num = int(input())
	if order_num == 0:
		break
	l = [int(x) for x in input().split()]
	print('{}'.format(statistics.pstdev(l)))


while True:
	n = int(input())
	if not n:
		break
	ss = list(map(int, input().split()))
	m = sum(ss) / n
	a2 = sum([(s - m) ** 2 / n for s in ss])
	print(a2 ** 0.5)


while list:
	N = int(input())
	if not N:
		break
	(*A,) = map(int, input().split())
	V = sum(A) / N
	print((sum(((a - V) ** 2 for a in A)) / N) ** 0.5)


import statistics
while True:
	num = int(input())
	if num == 0:
		break
	data = list(map(int, input().split()))
	print('{:.5f}'.format(statistics.pstdev(data)))


import statistics
while True:
	s = int(input())
	if s == 0:
		break
	else:
		lst = list(map(int, input().split()))
	print('{0:.8}'.format(statistics.pstdev(lst)))


while 1:
	sm2 = 0
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	for x in s:
		sm2 += (x - m) ** 2
	print((sm2 / n) ** 0.5)


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	s = map(int, input().split())
	print('{:.5f}'.format(statistics.pstdev(s)))


import math
while 1:
	n = int(input())
	if n == 0:
		break
	ss = list(map(float, input().split()))
	a = sum(ss) / n
	s = (sum([(s - a) ** 2 for s in ss]) / n) ** 0.5
	print('{0:.6f}'.format(s))


while True:
	n = int(input())
	if n == 0:
		break
	list = [int(s) for s in input().split()]
	m = sum(list) / n
	x = 0
	for i in range(n):
		x += (list[i] - m) ** 2
	a = (x / n) ** 0.5
	print(a)


import math
while True:
	n = int(input())
	if n == 0:
		break
	x = list(map(int, input().split()))
	ave = sum(x) / n
	a = 0
	for i in x:
		a += (i - ave) ** 2 / n
	print(math.sqrt(a))


import statistics
while True:
	n = int(input())
	if n == 0:
		break
	list_s = list(map(int, input().split()))
	print(statistics.pstdev(list_s))


while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	a = 0
	for i in s:
		a += (i - m) ** 2
	print((a / n) ** 0.5)


while 1:
	n = int(input())
	if n == 0:
		break
	s = input().split()
	a = sum([int(x) for x in s]) / n
	print((sum([int(x) ** 2 for x in s]) / n - a * a) ** 0.5)


while True:
	N = int(input())
	if N == 0:
		break
	A = list(map(int, input().split()))
	avg = sum(A) / N
	sig = sum([(a - avg) ** 2 for a in A])
	print((sig / N) ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	m = sum(s) / n
	print('{0:.5f}'.format(math.sqrt(sum([(x - m) ** 2 for x in s]) / n)))


import math
while True:
	n = eval(input())
	if n == 0:
		break
	s = [eval(x) for x in input().split()]
	m = sum(s) / n
	sd = math.sqrt(sum([(x - m) ** 2 for x in s]) / n)
	print(sd)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(float, input().split()))
	m = sum(s) / n
	print(math.sqrt(sum([(i - m) ** 2 for i in s]) / n))


while True:
	n = int(input())
	if n == 0:
		break
	data = list(map(int, input().split()))
	m = sum(data) / n
	v = 0
	for d in data:
		v += (d - m) ** 2
	print((v / n) ** 0.5)


import statistics
while True:
	n = input()
	if n == '0':
		break
	l = map(float, input().split())
	print(statistics.pstdev(l))


import statistics as stats
while True:
	n = int(input())
	if n == 0:
		break
	data = list(map(int, input().split()))
	SD = stats.pstdev(data)
	print('{:.5f}'.format(SD))


while int(input()):
	s = list(map(int, input().split()))
	n = len(s)
	a = sum(s) / n
	print((sum((x * x for x in s)) / n - a * a) ** 0.5)


import statistics
while 1:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	x = statistics.pstdev(s)
	print('{:.8f}'.format(x))


while True:
	n = int(input())
	if n == 0:
		break
	(*s,) = list(map(int, input().split()))
	m = sum(s) / n
	v = 0
	for i in s:
		v += (i - m) ** 2
	ans = (v / n) ** (1 / 2)
	print(ans)


from math import *
while True:
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	sum_s = sum(s)
	m = sum_s / n
	print(sqrt(sum(((a - m) ** 2 for a in s)) / n))


while 1:
	r = 0
	S = 0
	n = int(input())
	if n == 0:
		break
	s = list(map(int, input().split()))
	a = sum(s) / n
	for i in s:
		S = (a - i) ** 2 / n
		r += S
	print(r ** 0.5)


import math
while True:
	n = int(input())
	if n == 0:
		break
	s = [int(x) for x in input().split()]
	a = math.sqrt(sum([(i - sum(s) / n) ** 2 for i in s]) / n)
	print('{:.8f}'.format(a))


while True:
	n = int(input())
	if n == 0:
		break
	si = list(map(int, input().split()))
	m = sum(si) / n
	func = lambda x: (x - m) ** 2
	print((sum(map(func, si)) / n) ** 0.5)


while True:
	N = int(input())
	if N == 0:
		break
	A = [int(a) for a in input().split()]
	m = sum(A) / N
	print((sum(map(lambda a: (a - m) ** 2, A)) / N) ** 0.5)


while input() != '0':
	n = list(map(int, input().split()))
	b = len(n)
	a = sum(n) / b
	print((sum(((x - a) ** 2 for x in n)) / b) ** 0.5)
	if n == 0:
		break