program bla;
var a,b,n,aux:int64;
begin
  readln(a,b);
  if a>b then
    begin
      aux:=a;
      a:=b;
      b:=aux;
    end;
  n:=0;
  While (b+n) mod (a+n)<>0 do
    inc(n);
  writeln(n);
end.