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>

int main(){
    double x1, y1, x2, y2;
    std::cin >> x1 >> y1 >> x2 >> y2;
    printf("%10.8f\n",std::sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)));
}