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<stdio.h>
#include<math.h>
int main()
{
    double x1,x2,y1,y2,dx,dy;
    scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);
    dx=x2-x1;
    dy=y2-y1;
    printf("%lf\n",sqrt(dx*dx+dy*dy));
}