import std.algorithm, std.array, std.container, std.range, std.bitmanip;
import std.numeric, std.math, std.bigint, std.random, core.bitop;
import std.string, std.regex, std.conv, std.stdio, std.typecons;

void main()
{
  auto rd = readln.split.map!(to!real);
  auto a = rd[0], b = rd[1];
  if (a < b) swap(a, b);
  if (a == b)
    writefln("%.6f", (a ^^ 2 + b ^^ 2).sqrt);
  else
    writefln("%.6f", (a ^^ 2 - b ^^ 2).sqrt);
}