import math
rL = input().split(' ')
m = []
for i in range(len(rL)):
    m.append(int(rL[i]))
def corToVec(x,y,x1,y1):
    return x1-x , y1-y
x = m[0]
y = m[1]
x1 = m[2]
y1 = m[3]
x2 = m[4]
y2 = m[5]
xv, yv = corToVec(x1,y1,x2,y2)
xv2,yv2 = corToVec(x1,y1,x,y)
SP = (xv * xv2)+(yv * yv2)
xv1, yv1 = corToVec(x2,y2,x1,y1)
xv21,yv21 = corToVec(x2,y2,x,y)
SP1 = (xv1 * xv21)+(yv1 * yv21)
#print(SP,SP1)
a = y1-y2
b = x2-x1
c = (x1*y2)-(x2*y1)
if((SP1 >= 0) and (SP >= 0)):
    AP = abs(a*x+b*y+c)/math.sqrt((a*a) + (b*b))
    print(AP)
else:
    vnx,vny = corToVec(x,y,x2,y2)
    vnx1,vny1 = corToVec(x,y,x1,y1)
    ans1 = math.sqrt((vnx*vnx)+(vny*vny))
    ans2 = math.sqrt((vnx1*vnx1)+(vny1*vny1))
    if(ans1 < ans2):
        print(ans1)
    else:
        print(ans2)