Problem:
Distance

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.

Sample Input

0 0 1 1

Sample Output

1.41421356

Solution in Ruby (judge verdict: Accepted)

#lines = <<'EOS'
#0 0 1 1
#EOS

lines = $stdin.read

array = lines.split("\n")

str = array[0]
x1  = str.split(" ")[0].to_f
y1  = str.split(" ")[1].to_f
x2  = str.split(" ")[2].to_f
y2  = str.split(" ")[3].to_f

diff = ((x1-x2)**2).abs + ((y1-y2)**2).abs
d    = Math.sqrt(diff)
puts "#{d}"