from math import sqrt
t = int(input())
end = 0
tav = []
while t > end:
k = 0
tab = []
while k < 2:
[tab.append(int(x)) for x in input().split() if x != '']
k += 1
length = sqrt((tab[3]-tab[0])**2\
+(tab[4]-tab[1])**2)
next_len = (tab[2]*2+tab[5]*2) - (length + tab[2]+tab[5])
if next_len < 0:
next_len = 0
elif length == 0:
if tab[2] > tab[5]:
next_len = 2 * tab[5]
else:
next_len = 2 * tab[2]
tav.append(next_len)
end += 1
print()
for i in tav:
print('{:.2f}'.format(i))
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