const nmax = 20000;
var fi,fo:text;
var fp:array[1..nmax,1..10] of integer;
    nrfp:array[1..nmax] of byte;
    sita:array[1..nmax] of integer;

function euler(n:longint):longint;
var i,p:longint;
begin
  p := n;
  for i := 1 to nrfp[n] do
    p := (p div fp[n][i])*(fp[n][i] - 1);
  euler := p
end;

function ggt1(n1,n2:longint):longint;
var j:integer;
begin
  ggt1 := 2;
  for j := 1 to nrfp[n2] do
    if n1 mod fp[n2][j]=0 then exit;
  ggt1:=1;
end;


var dx,dy,mini,maxi,i,j,x1,x2,y1,y2,ct,max,d,aux,nrprim:longint;

begin
  assign(fi,'mins.in'); reset(fi);
  readln(fi,x2,y2);
  close(fi);

  dx := x2-x1-1;  //calcul coordonate "active"
  dy := y2-y1-1;
  if dx<dy then begin mini := dx; maxi := dy end
  else begin mini := dy; maxi := dx end;
  nrfp[1] := 1;
  fp[1][1] := 1;

  //construiesc tabloul de factori primi
  for i := 2 to mini do
   if sita[i]=0 then
     begin
       j := i;
       while j<=mini do
         begin
           inc(nrfp[j]);
           fp[j][nrfp[j]]:=i;
           sita[j]:=1;
           inc(j,i)
         end;
     end;


  for i := 2 to mini do
      ct := ct + euler(i);

  ct := ct*2;

  ct := ct+maxi-mini;

  for i := mini+1 to maxi do
    for j := 2 to mini do
      if ggt1(i,j)=1 then
       inc(ct);


  assign(fo,'mins.out'); rewrite(fo);
  writeln(fo,ct+1);
  close(fo);

end.