import math
def dis(x1,y1,x2,y2):
    l = (x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)
    l = math.sqrt(l)
    return l

a = list(map(int,input().split()))
b = list(map(int,input().split()))
c = list(map(int,input().split()))

print(format(dis(a[0],b[0],a[1],b[1])+dis(a[0],c[0],a[1],c[1])+dis(b[0],c[0],b[1],c[1]),".2f"))