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.Scanner;

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