a=input().split()
b=input().split()
c=input().split()
d1=((int(a[0])-int(b[0]))**2+(int(a[1])-int(b[1]))**2)**0.5
d2=((int(b[0])-int(c[0]))**2+(int(b[1])-int(c[1]))**2)**0.5
d3=((int(a[0])-int(c[0]))**2+(int(a[1])-int(c[1]))**2)**0.5
d=round(d1+d2+d3,2)
print(d)