var a:array[0..9,1..1000000]of integer;
    n:longint; s:int64;

procedure init;
var f:text; i,j:longint;
begin
  assign(f, 'fractii.in');
  reset(f);
  read(f,n);
  close(f);
  s:=0;
  for i:=0 to 9 do
  for j:=1 to n do
    a[i,j]:=0;
end;

procedure rez;
var f:text;
begin
  assign(f, 'fractii.out');
  rewrite(f);
  write(f,s);
  close(f);
end;

procedure calc;
var i,j,k,s1:longint;
begin
  for i:=2 to 1000 do
  if a[0,i]=0
  then begin
    j:=i*2;
    while j<=n do
    begin
      inc(a[0,j]);
      a[a[0,j],j]:=i;
      inc(j,i);
    end;
  end;
  s:=2*n-1;
  for i:=2 to n do
  if a[0,i]=0
  then
  begin
   s:=s+(n-i-(n-i)div i)*2;
   {write(n-i-(n-i)div i,' ');}
  end
  else
  begin
     s1:=0;
     for k:=1 to a[0,i] do s1:=s1+(n-i)div a[k,i];
     for k:=1 to a[0,i]-1 do
        for j:=k+1 to a[0,i] do
          s1:=s1-(n-i)div(a[k,i]*a[j,i]);
     {write(n-i-s1,' ');}
     s:=s+(n-i-s1)*2;
  end;
end;

begin
 init;
 calc;
 rez;
end.