program fractii;
var i,n:longint;
    nf:real;
    f:text;

function nrdiv(x:longint):longint;
var nd,i:longint;
 begin
  nd:=1;
  i:=2;
  repeat
   if x mod i=0 then
    begin
     nd:=nd+ n div i-1;
     while x mod i =0 do
      x:=x div i;
    end;
   i:=i+1;
  until x=1;
  nrdiv:=nd
 end;


begin
 assign(f,'cifre.in');
 reset(f);
 readln(f,n);
 close(f);
 nf:=n;
 for i:=2 to n do
  nf:=nf+n - nrdiv(i);
 assign(f,'fractii.out');
 rewrite(f);
 write(f,nf:0:0);
 close(f);
end.