#include <bits/stdc++.h>
using namespace std;

signed main(){
  double a, b; cin >> a >> b;
  if( a == b )
    cout << fixed << setprecision( 13 ) << sqrt( a * a + a * a ) << endl, exit( 0 );
  if( not ( a > b ) )
    swap( a, b );
  cout << fixed << setprecision( 13 ) << sqrt( a * a - b * b ) << endl;
  return 0;
}