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)

input = []
STDIN.gets.split(' ').each{|v| input.push(v.to_f) }

puts Math.sqrt((input[2] - input[0])*(input[2] - input[0]) + (input[3] - input[1])*(input[3] - input[1]))