x = int(input())
y = int(input())
z = int(input())
x2 = int(input())
y2 = int(input())
z2 = int(input())
if x>y and x2>y2:
      m = (x-y)/2
      m2 = (x2-y2)/2
else:
      m = (y-x)/2
      m2 = (y2-x2)/2
bok_s1 = (m**2+z**2)**0.5
bok_s2 = (m2**2+z2**2)**0.5
p_1 = 2*bok_s1+y+x
p_2 = 2*bok_s2+y2+x2

print(p_1+p_2)