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.*;

public class Main {
	public static void main(String args[]){
		double[] r = new double[4];
		
		Scanner scn = new Scanner(System.in);
		String inl = scn.nextLine();
		String[] part = inl.split(" ");
		for(int i = 0 ; i < 4 ; i++){
			r[i] = Double.parseDouble(part[i]);
		}
		System.out.println(Math.sqrt(Math.pow( (r[0] - r[2]) , 2) + Math.pow( (r[1] - r[3]) , 2)));
	}
}