import java.util.*;
import java.lang.*;
import java.io.*;
class Ideone
{
{
Scanner in
= new Scanner
(System.
in); double b=in.nextDouble();
double a=in.nextDouble();
double inf = 1.0 / 0;
double c;
c
=(b
<a
)?inf
:Math.
sqrt(b
*b
-a
*a
); }
}
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