import std; void main() { double r, d; scan(r, d); auto ans = sqrt(d * d - r * r); writeln(ans); } void scan(T...)(ref T a) { string[] ss = readln.split; foreach (i, t; T) a[i] = ss[i].to!t; } T read(T)() { return readln.chomp.to!T; } T[] reads(T)() { return readln.split.to!(T[]); } alias readint = read!int; alias readints = reads!int;