Write a program which calculates the distance between two points P1(x1, y1) and P2(x2, y2).



Input

Four real numbers x1, y1, x2 and y2 are given in a line.

Output

Print the distance in real number. The output should not contain an absolute error greater than 10-4.

Example

Input

0 0 1 1


Output

1.41421356

Source: aizu | Difficulty: UNKNOWN_DIFFICULTY


Solutions:
(x1, y1, x2, y2) = map(float, input().split())
n = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** (1 / 2)
print('{:.8f}'.format(n))


import math
(X1, Y1, X2, Y2) = map(float, input().split())
print(math.sqrt((X2 - X1) * (X2 - X1) + (Y2 - Y1) * (Y2 - Y1)))


N = list(map(float, input().split()))
S = ((N[0] - N[2]) ** 2 + (N[1] - N[3]) ** 2) ** 0.5
print(S)


(a, b, c, d) = map(float, input().split())
x = abs(a - c)
y = abs(b - d)
z = x ** 2 + y ** 2
print(pow(z, 0.5))


import math
(a, b, c, d) = map(float, input().split())
X = a - c
Y = b - d
print(math.sqrt(X ** 2 + Y ** 2))


import math
m = [float(i) for i in input().split()]
x = m[2] - m[0]
y = m[3] - m[1]
print(math.sqrt(float(x * x + y * y)))


(x1, y1, x2, y2) = list(map(float, input().split()))
import math
print(math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
d = (x2 - x1) ** 2 + (y2 - y1) ** 2
print(math.sqrt(d))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(round(math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2), 7))


(v, w, x, y) = map(float, input().split())
print(float(abs(v - x) ** 2 + abs(w - y) ** 2) ** (1 / 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
a = x1 - x2
b = y1 - y2
c = a ** 2 + b ** 2
print(math.sqrt(c))


(x1, y1, x2, y2) = map(float, input().split())
l = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(l)


import math
(x1, y1, x2, y2) = map(float, input().split())
d = math.sqrt(pow(x1 - x2, 2) + pow(y1 - y2, 2))
print(d)


import math
(x1, y1, x2, y2) = map(float, input().split())
L = math.sqrt(pow(x1 - x2, 2) + pow(y1 - y2, 2))
print(str(L))


(x1, y1, x2, y2) = map(float, input().split())
ans = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(ans)


import math
(x1, y1, x2, y2) = list(map(float, input().split()))
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
p = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(p)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(f'{math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2):0.9f}')


from math import sqrt
(a, b, c, d) = map(float, input().split())
print(sqrt((c - a) ** 2 + (d - b) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
L = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)
print(math.sqrt(L))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt(abs(x2 - x1) ** 2 + abs(y2 - y1) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print('{0:5f}'.format(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)))


(x1, y1, x2, y2) = map(float, input().split())
print('%.05f' % ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split(' '))
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


(x1, x2, y1, y2) = map(float, input().split())
import math
print(math.sqrt((x1 - y1) ** 2 + (x2 - y2) ** 2))


import math
n = list(map(float, input().split()))
print(math.sqrt((n[2] - n[0]) ** 2 + (n[3] - n[1]) ** 2))


(a, b, c, d) = map(float, input().split())
print(((c - a) ** 2 + (d - b) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
z = x1 - x2 + (y1 - y2) * 1j
print(abs(z))


import math
(a, b, c, d) = map(float, input().split())
print('{:.10f}'.format(math.sqrt((a - c) ** 2 + (b - d) ** 2)))


import math
(x1, y1, x2, y2) = map(float, input().split())
d = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(d)


(w, x, y, z) = map(float, input().split())
print('%5f' % ((w - y) ** 2 + (x - z) ** 2) ** 0.5)


from math import sqrt
(x1, y1, x2, y2) = map(float, input().split())
print(sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print('%.6f' % ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
print(f'{((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5:.6f}')


import math
(a, b, c, d) = map(float, input().split())
print(math.sqrt((c - a) ** 2 + (d - b) ** 2))


import math
a = list(map(float, input().split()))
d = math.sqrt(pow(a[0] - a[2], 2) + pow(a[1] - a[3], 2))
print(d)


import math
(x, y, X, Y) = [float(i) for i in input().split()]
print(math.sqrt((x - X) ** 2 + abs(y - Y) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
distance = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)
print(distance)


from math import hypot
(a, b, c, d) = map(float, input().split())
e = hypot(a - c, b - d)
print(e)


(x_1, y_1, x_2, y_2) = map(float, input().split())
d_2 = (x_2 - x_1) ** 2 + (y_2 - y_1) ** 2
d = d_2 ** 0.5
print(d)


import math
(x1, x2, y1, y2) = map(float, input().split())
d = math.hypot(y1 - x1, y2 - x2)
print(float(d))


import math
(x1, y1, x2, y2) = map(float, input().split())
l = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
print(l)


(a, b, c, d) = map(float, input().split())
print(((c - a) ** 2 + (d - b) ** 2) ** (1 / 2))


(x1, y1, x2, y2) = map(float, input().split())
print(abs(complex(x1 - x2, y1 - y2)))


(x1, y1, x2, y2) = [float(_) for _ in input().split()]
ans = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5
print(ans)


import math
(a, b, c, d) = map(float, input().split())
print(math.sqrt((c - a) ** 2 + (d - b) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
a = (x2 - x1) ** 2 + (y2 - y1) ** 2
print(math.sqrt(a))


[x1, y1, x2, y2] = [float(item) for item in input().split()]
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
t = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
print(t)


import math
(a, b, c, d) = map(float, input().split())
print(math.sqrt((a - c) ** 2 + (b - d) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
p = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(f'{p:.8f}')


(x1, y1, x2, y2) = list(map(float, input().split()))
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


(x1, x2, y1, y2) = map(float, input().split())
print(((x1 - y1) ** 2 + (x2 - y2) ** 2) ** (1 / 2))


(x1, y1, x2, y2) = map(float, input().split())
a = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(a)


(x1, x2, y1, y2) = map(float, input().split())
print(((x1 - y1) ** 2 + (x2 - y2) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)))


import math
(x1, y1, x2, y2) = map(float, input().split())
a = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
print(a)


(x1, y1, x2, y2) = map(float, input().split())
dist = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)
print(dist)


x = list(map(float, input().split()))
(x1, y1, x2, y2) = (x[0], x[1], x[2], x[3])
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


(a, b, c, d) = map(float, input().split())
dx = a - c
dy = b - d
dd = (dx * dx + dy * dy) ** 0.5
print(dd)


import math
(a, b, c, d) = map(float, input().split())
x = (a - c) ** 2
y = (b - d) ** 2
l = math.sqrt(x + y)
print(l)


(x1, y1, x2, y2) = map(float, input().split())
print(f'{((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5:.6f}')


(ax1, ay1, bx1, by1) = map(float, input().split())
print(((bx1 - ax1) ** 2 + (by1 - ay1) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
ans = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)
print(ans)


import math
(a, b, x, y) = map(float, input().split())
f = x - a
d = ((x - a) * (x - a) + (y - b) * (y - b)) ** (1 / 2)
print('%5f' % d)


(x1, y1, x2, y2) = map(float, input().split())
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** (1 / 2))


(x1, y1, x2, y2) = [float(n) for n in input().split()]
print(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
ans = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(ans)


(x1, y1, x2, y2) = list(map(float, input().split()))
d = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(d)


(x1, y1, x2, y2) = map(float, input().split())
a = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)
print(a ** (1 / 2))


(x1, y1, x2, y2) = map(float, input().split())
print('{0:.6f}'.format(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5))


import math
(x1, y1, x2, y2) = map(float, input().split())
print('%f' % math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


(x1, y1, x2, y2) = [float(_) for _ in input().split()]
k = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)
print(k)


(x1, y1, x2, y2) = map(float, input().split())
print('%.8f' % ((y2 - y1) ** 2 + (x2 - x1) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().strip().split())
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print(abs(complex(x2 - x1, y2 - y1)))


import math
(x1, y1, x2, y2) = map(float, input().split(' '))
print(math.sqrt(pow(x1 - x2, 2) + pow(y1 - y2, 2)))


(x1, y1, x2, y2) = map(float, input().split())
ans = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5
print(round(ans, 6))


import math
(x1, y1, x2, y2) = map(float, input().split())
sum = (x1 - x2) ** 2 + (y1 - y2) ** 2
print(math.sqrt(sum))


(x1, y1, x2, y2) = map(float, input().split())
print(format(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5, '.5f'))


(x1, y1, x2, y2) = [float(i) for i in input().split()]
print('{:.8f}'.format(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5))


import math
x = list(map(float, input().split()))
print(math.sqrt((x[2] - x[0]) ** 2 + (x[3] - x[1]) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print((abs(x1 - x2) ** 2 + abs(y1 - y2) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(f'{math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2):.5f}')


(x1, y1, x2, y2) = [float(i) for i in input().split()]
d = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5
print(d)


import math
(x1, y1, x2, y2) = map(float, input().split())
z = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(z)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(f'{math.hypot(x2 - x1, y2 - y1):.5f}')


(x, y, p, q) = map(float, input().split())
print(((x - p) ** 2 + (y - q) ** 2) ** (1 / 2))


(x1, y1, x2, y2) = map(float, input().split())
d2 = (x1 - x2) ** 2 + (y1 - y2) ** 2
print(d2 ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
distance = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(distance)


import math
i = list(map(float, input().split()))
x = (i[2] - i[0]) ** 2
y = (i[3] - i[1]) ** 2
print(math.sqrt(x + y))


from math import sqrt
(a, b, c, d) = map(float, input().split())
print(sqrt((a - c) ** 2.0 + (b - d) ** 2.0))


import math
(a, b, c, d) = map(float, input().split())
print(math.sqrt(pow(abs(a - c), 2) + pow(abs(b - d), 2)))


(x1, y1, x2, y2) = map(float, input().split())
cal = float(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5)
print(cal)


(x1, y1, x2, y2) = map(float, input().split())
print(((x2 - x1) ** 2 + (y1 - y2) ** 2) ** 0.5)


import math as mp
l = list(map(float, input().split()))
print(mp.sqrt((l[0] - l[2]) ** 2 + (l[1] - l[3]) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt((y2 - y1) ** 2 + (x2 - x1) ** 2))


import math
(x_1, y_1, x_2, y_2) = map(float, input().split())
print(math.sqrt((x_1 - x_2) ** 2 + (y_1 - y_2) ** 2))


import math
(a, b, c, d) = map(float, input().split())
print(format(math.sqrt(pow(c - a, 2) + pow(d - b, 2)), '.5f'))


data = list(map(float, input().split()))
print(((data[2] - data[0]) ** 2 + (data[3] - data[1]) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
D = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2.0)
print(D)


(x1, y1, x2, y2) = [float(s) for s in input().split(' ')]
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


(x, y, x_, y_) = map(float, input().split())
X = abs(x - x_) ** 2
Y = abs(y - y_) ** 2
print('{:.4f}'.format((X + Y) ** (1 / 2)))


(x1, y1, x2, y2) = [float(x) for x in input().split()]
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** (1 / 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
n = (x1 - x2) ** 2 + (y1 - y2) ** 2
n1 = math.sqrt(n)
print(n1)


import math
(x1, y1, x2, y2) = (float(i) for i in input().split())
print(math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


(o, p, q, r) = [float(i) for i in input().split()]
print(format(((q - o) ** 2 + (r - p) ** 2) ** (1 / 2), '.8f'))


(a, b, c, d) = map(float, input().split())
k = c - a
l = d - b
n = (k * k + l * l) ** (1 / 2)
print('{:.8f}'.format(n))


(x1, y1, x2, y2) = map(float, input().split())
print('{:.5f}'.format(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5))


(x1, y1, x2, y2) = map(float, input().split())
print((abs(x2 - x1) ** 2 + abs(y2 - y1) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
x = (x2 - x1) ** 2
y = (y2 - y1) ** 2
print((x + y) ** 0.5)


import math
(x1, y1, x2, y2) = [float(d) for d in input().split()]
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


(a, b, c, d) = map(float, input().split())
z = ((a - c) ** 2 + (b - d) ** 2) ** (1 / 2)
print(z)


(x1, y1, x2, y2) = map(float, input().split())
r = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)
print(r)


import math
(x1, y1, x2, y2) = [float(s) for s in input().split()]
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
a = x1 - x2
b = y1 - y2
x = math.sqrt(a ** 2 + b ** 2)
print(x)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(f'{math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2):.8f}')


(A, B, C, D) = map(float, input().split())
E = (C - A) ** 2
F = (D - B) ** 2
print(float(E + F) ** (1 / 2))


import math
(a, b, c, d) = map(float, input().split())
e = (c - a) ** 2 + (d - b) ** 2
print(math.sqrt(e))


(x1, y1, x2, y2) = map(float, input().split())
d = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** (1 / 2)
print(d)


(x, y, p, q) = map(float, input().split())
ans = ((p - x) ** 2 + (q - y) ** 2) ** 0.5
print(f'{ans:.8f}')


(x1, y1, x2, y2) = map(float, input().split())
print('{:.5f}'.format(((y2 - y1) ** 2 + (x2 - x1) ** 2) ** 0.5))


(a, b, c, d) = map(float, input().split())
x = c - a
y = d - b
print((x ** 2 + y ** 2) ** (1 / 2))


import math
(a, b, c, d) = map(float, input().split())
taiga = (c - a) ** 2 + (d - b) ** 2
print(math.sqrt(taiga))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt(pow(x1 - x2, 2) + pow(y1 - y2, 2)))


import math
(x1, y1, x2, y2) = map(float, input().split())
dx = x1 - x2
dy = y1 - y2
print(math.sqrt(dx * dx + dy * dy))


from math import sqrt
(a, b, c, d) = map(float, input().split())
e = sqrt((c - a) ** 2 + (d - b) ** 2)
print(e)


import math
(a, b, c, d) = map(float, input().split())
t = pow(a - c, 2) + pow(b - d, 2)
print(math.sqrt(t))


(x1, y1, x2, y2) = map(float, input().split())
print(((x1 - x2) ** 2.0 + (y1 - y2) ** 2.0) ** 0.5)


(a, b, c, d) = map(float, input().split())
e = (c - a) ** 2
f = (d - b) ** 2
print(f'{(e + f) ** (1 / 2):.8f}')


(x1, y1, x2, y2) = map(float, input().split())
print(f'{abs(complex(x1 - x2, y1 - y2)):.5f}')


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.hypot(x1 - x2, y1 - y2))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
distance = (x2 - x1) ** 2 + (y2 - y1) ** 2
print(distance ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
x = x1 - x2
y = y1 - y2
ans = math.sqrt(x ** 2 + y ** 2)
print(ans)


(a, b, c, d) = map(float, input().split())
l = ((a - c) ** 2 + (b - d) ** 2) ** (1 / 2)
l = round(l, 6)
print(l)


import math
(a, b, c, d) = map(float, input().split())
n = (a - c) ** 2 + (b - d) ** 2
print(math.sqrt(n))


(x1, y1, x2, y2) = map(float, input().split())
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split(' '))
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


(a, b, c, d) = map(float, input().split())
temp = ((a - c) ** 2 + (b - d) ** 2) ** 0.5
print(temp)


(x1, y1, x2, y2) = map(float, input().split())
r = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print('{:.8f}'.format(r))


(x1, y1, x2, y2) = map(float, input().split())
ans = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** (1 / 2)
print(ans)


import math
(x1, y1, x2, y2) = map(float, input().split())
a = (x1 - x2) ** 2
b = (y1 - y2) ** 2
print(math.sqrt(a + b))


import math
(a, aa, b, bb) = map(float, input().split())
A = math.sqrt(abs(a - b) ** 2 + abs(aa - bb) ** 2)
print(A)


(x1, y1, x2, y2) = map(float, input().split())
d = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print('{:.6f}'.format(d))


(x1, y1, x2, y2) = map(float, input().split())
print(f'{((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5:8f}')


import math
(x1, y1, x2, y2) = map(float, input().split())
D = (x2 - x1) ** 2 + (y2 - y1) ** 2
d = math.sqrt(D)
print(d)


import math
(a, b, c, d) = map(float, input().split())
x = abs(c - a)
y = abs(d - b)
S = (x ** 2 + y ** 2) ** 0.5
print(S)


import math
(x1, y1, x2, y2) = [float(x) for x in input().split()]
print(math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


import math
(x, y, X, Y) = [float(i) for i in input().split()]
print(math.sqrt((x - X) ** 2 + (y - Y) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print('{0}'.format(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** (1 / 2)))


from math import sqrt
(x1, y1, x2, y2) = map(float, input().split())
print(sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


x = list(map(float, input().split()))
y = round(((x[0] - x[2]) ** 2 + (x[1] - x[3]) ** 2) ** 0.5, 8)
print(y)


(x1, y1, x2, y2) = map(float, input().split())
print(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2))


(a, b, c, d) = map(float, input().split())
dis = ((c - a) ** 2 + (d - b) ** 2) ** 0.5
print(format(dis, '.8f'))


(x1, y1, x2, y2) = map(float, input().split())
print(float(abs(x1 - x2) ** 2 + abs(y1 - y2) ** 2) ** (1 / 2))


(x, y, xx, yy) = map(float, input().split())
print('%5f' % ((x - xx) ** 2 + (y - yy) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(lambda x: float(x), input().split(' '))
print(((x1 - x2) ** 2.0 + (y1 - y2) ** 2.0) ** 0.5)


a = list(map(float, input().split()))
print((abs(a[0] - a[2]) ** 2 + abs(a[1] - a[3]) ** 2) ** (1 / 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
x = x2 - x1
y = y2 - y1
print(math.hypot(x, y))


(x1, y1, x2, y2) = map(float, input().split())
print('{:.8f}'.format(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5))


from math import *
(x1, y1, x2, y2) = map(float, input().split())
print(hypot(x1 - x2, y1 - y2))


import math
(x1, y1, x2, y2) = map(float, input().split())
P = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
print(P)


import math
(x1, x2, y1, y2) = map(float, input().split())
print(math.sqrt((y1 - x1) ** 2 + (y2 - x2) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(round(math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2), 5))


from math import hypot
(a, b, c, d) = map(float, input().split())
print(hypot(a - c, b - d))


(a, b, c, d) = list(map(float, input().split()))
print('%.5f' % ((c - a) ** 2 + (b - d) ** 2) ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
D = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** (1 / 2)
print(D)


(x1, y1, x2, y2) = map(float, input().split())
z = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print('{0:.5f}'.format(z))


(x1, y1, x2, y2) = map(float, input().split())
import math
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


(a, b, c, d) = map(float, input().split())
print('{:.5f}'.format((abs(a - c) ** 2 + abs(b - d) ** 2) ** 0.5))


import math
(x1, y1, x2, y2) = (float(i) for i in input().split())
print(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))


(x1, y1, x2, y2) = map(float, input().split())
print(((y2 - y1) ** 2 + (x2 - x1) ** 2) ** (1 / 2))


(x1, y1, x2, y2) = map(float, input().split())
print('%.8f' % ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
print(f'{math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2):.5f}')


(x1, y1, x2, y2) = map(float, input().split())
d = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(d)


import math
(x1, y1, x2, y2) = map(float, input().split())
a = x2 - x1
b = y2 - y1
d = math.hypot(a, b)
print(d)


(a, b, c, d) = map(float, input().split())
print(abs(complex(c - a, d - b)))


import math
(x1, y1, x2, y2) = map(float, input().split())
x = x1 - x2
y = y1 - y2
h = x ** 2 + y ** 2
print(h ** 0.5)


(x1, y1, x2, y2) = map(float, input().split())
dist = ((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5
print(dist)


import math
(a, b, c, d) = map(float, input().split())
ans = math.sqrt((c - a) ** 2 + (d - b) ** 2)
print(round(ans, 8))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt(pow(x2 - x1, 2) + pow(y2 - y1, 2)))


(x1, y1, x2, y2) = [float(i) for i in input().split()]
print(((x1 - x2) ** 2 + (y1 - y2) ** 2) ** 0.5)


import math
(x1, y1, x2, y2) = map(float, input().split())
dist = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(dist)


import math
(a, b, c, d) = map(float, input().split())
print(((c - a) ** 2 + (d - b) ** 2) ** 0.5)


(a, b, c, d) = map(float, input().split())
t = (a - c) ** 2 + (b - d) ** 2
print(t ** (1 / 2))


(a, b, c, d) = map(float, input().split())
import math
x = math.sqrt((c - a) ** 2 + (d - b) ** 2)
print('{:.5f}'.format(x))


(a, b, c, d) = map(float, input().split())
r = ((c - a) ** 2 + (d - b) ** 2) ** (1 / 2)
print(f'{r:5f}')


(a, b, c, d) = map(float, input().split())
print(float(abs(a - c) ** 2 + abs(b - d) ** 2) ** (1 / 2))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.sqrt(abs(x2 - x1) ** 2 + abs(y2 - y1) ** 2))


(a, b, c, d) = map(float, input().split())
k = ((c - a) * (c - a) + (d - b) * (d - b)) ** (1 / 2)
print('{:8f}'.format(k))


import math
(x1, y1, x2, y2) = map(float, input().split())
print(math.hypot(x2 - x1, y2 - y1))


(x1, y1, x2, y2) = map(float, input().split())
print(((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5)


(a, b, x, y) = map(float, input().split())
print(((a - x) ** 2 + (b - y) ** 2) ** 0.5)


(a, b, c, d) = map(float, input().split())
print(((a - c) ** 2 + (b - d) ** 2) ** 0.5)


from math import sqrt
(x1, y1, x2, y2) = list(map(float, input().split()))
print(sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2))


import math
(x1, y1, x2, y2) = map(float, input().split(' '))
res = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(res)