Mohamed loves Travelling. but as travelling take a lot of time from him. He needs your help to calculate the distance between his current location and location of the place he wants to go. Location of each place will be given in (x, y) coordinates.

Input

Input will be 4 doubles x1, y1, x2, y2 represent two locations (Mohamed's current location, location of the place he wants to go to.)

Where 0 <= x1, y1, x2, y2 <= 10000.

Output

Print distance between 2 locations as "Euclidean distance".

Print a newline after each test case.

Example

Input:
0 2 4 6

Output:
5.65685

Please note:

You can find "Euclidean distance" formula in http://www.cut-the-knot.org/pythagoras/DistanceFormula.shtml.

you can use sqrt() function to get square root. sqrt() take a double or a float number for example

cout << sqrt(4.0) << endl; // will print 2.0
And to use sqrt() function please include cmath library. Just put #include <cmath> in you code.