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 PYTHON):

Solution:
from __future__ import division, print_function
from sys import stdin
from math import hypot, sqrt
x1, y1, x2, y2 = (float(s) for s in stdin.readline().split())
print('{:.4f}'.format(hypot(x1-x2, y1-y2)))