program lcm;
var a,b,n,p:int64;
begin
      read(a,b);
      if a>b then
        begin
            p:=a;
            a:=b;
            b:=p;
        end;
      n:=0;
      while (b+n) mod (a+n)<>0 do
            n:=n+1;
      write(n);
end.