program nume;
var a,b,aux,n: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
       n:=n+1;
       writeln(n);
end.