program pascal;
var
 f:text;
 n,i,j,count:longint;
function cmmdc(a,b:longint):boolean;
begin
  while a<>b do
    if a>b then
       a:=a-b
    else b:=b-a;
  if a=1 then
    cmmdc:=true
  else cmmdc:=false;
end;

begin
  assign(f,'fractii.in');
  reset(f);
  read(f,n);
  close(f);
  
  count:=1;
  for i:=1 to n-1 do begin
    j:=i+1;
    if i mod 2 = 0 then
     while j<=n do begin
       if cmmdc(i,j) then
         inc(count,2);
       inc(j,2);
     end
    else
     for j:=i+1 to n do
       if cmmdc(i,j) then
         inc(count,2);
  end;
  assign(f,'fractii.out');
  rewrite(f);
  write(f,count);
  close(f);
end.