Problem: 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

Solution (in JAVA):

Solution:

import java.util.*;

class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
double x1,x2,y1,y2;
x1 =sc.nextDouble();
y1 =sc.nextDouble();
x2 =sc.nextDouble();
y2 =sc.nextDouble();
if(x1==x2) System.out.println(y2-y1);
else if(y1==y2) System.out.println(x2-x1);
else
System.out.println(Math.sqrt(Math.pow(x2-x1,2)+Math.pow(y2-y1,2)));
}
}