program mire;
var m,p,min,c,d:int64;
a,b,n,i:longint;
function cmmdc(x,y:longint):longint;
var r,aux:longint;
begin
   while x<>y do
     if x>y then
       x:=x-y
     else
        y:=y-x;
  cmmdc:=x;
end;
begin
   read(a,b);
     min:=1000000000;
      for i:=0 to a*b do
         begin
           c:=a+i;
           d:=b+i;
           m:=cmmdc(c,d);
           p:=c*d div m;
           if p<min then
             begin
                min:=p;
                n:=i;
                if (min=c) or (min=d) then
                  break;
             end;
         end;
       write(n);
end.