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 CPP):

Solution:
#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

int main(){
  double x1, y1, x2, y2, x, y;
  cin>>x1>>y1>>x2>>y2;
  x=x2-x1;
  y=y2-y1;
  printf("%f\n", sqrt(x*x+y*y));
  return 0;
}