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 <bits/stdc++.h>
using namespace std;
 
int main() {
  double x1, x2, y1, y2, a;
  cin >> x1 >> y1 >> x2 >> y2;
  
  a = (x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2);
  a = sqrt(a);
  printf("%.6lf\n", a);
}