def find_min(a, b, c, d):
ab = Vector(a, b)
ac = Vector(a, c)
ad = Vector(a, d)
cd = Vector(c, d)
ca = Vector(c, a)
cb = Vector(c, b)
bd = Vector(b, d)
if intersect(a,b,c,d):
print("Not intersection")
return ab.length()
elif ab.cros_product(ac)*ab.cros_product(ad) <= 0 and cd.cros_product(ca)*cd.cros_product(cb) <= 0:
print("Intersection")
return min(ac.length()+cb.length(), ad.length()+bd.length())
else:
print("Not intersection")
return ab.length()
