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:
public class Main {
	public static void main(String[] args){
		java.util.Scanner scan = new java.util.Scanner(System.in);
			double x1 = scan.nextDouble();
			double y1 = scan.nextDouble();
			double x2 = scan.nextDouble();
			double y2 = scan.nextDouble();
			double ans =Math.sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
			System.out.println(ans);

	}

}