006. Distance

006. Distance

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Find the distance between two 2D points. Remember that the distance formula is 

𝑑=(𝑥2−𝑥1)2+(𝑦2−𝑦1)2‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾√$d=\sqrt{(x_2-x_1{)}^2+(y_2-y_1{)}^2}$

math.sqrt will calculate the square root of a number. Also, you also have to add the line  import math at the top of the program.

Input

The first two lines contain the X and Y coordinates of the first point respectively. The second two lines contain the X and Y coordinates of the second point respectively. Each coordinate will have an integer value between -1000 and 1000, inclusive.

Output

A double N representing the distance between the two points

Examples

input

Copy

1
1
2
2

output

Copy

1.4142135623730951

input

Copy

1
1
1
1

output

Copy

0.0