有手就行

x1,y1=map(float,input().split())
x2,y2=map(float,input().split())
x3,y3=map(float,input().split())
a1=((x2-x1)**2+(y2-y1)**2)**0.5
a2=((x3-x1)**2+(y3-y1)**2)**0.5
a3=((x3-x2)**2+(y3-y2)**2)**0.5
print("%.2f"%(a1+a2+a3))