import math
x1= float(input()) 
y1 = float(input())
x2 = float(input())
y2 = float(input())
x3 = float(input())
y3 = float(input())

side1 = math.sqrt((x2 - x1)**2 + (y2 - y1)**2)
side2 = math.sqrt((x3 - x2)**2 + (y3 - y2)**2)
side3 = math.sqrt((x1 - x3)**2 + (y1 - y3)**2)

perimetr = side1 + side2 + side3

print("Периметр треугольника: ", perimetr)