program task_c;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
 n:longint;
 ans:int64;
 f:text;
begin
assign(f,'pair.in');
reset(f);
readln(f,n);
close(f);
ans:=0;
ans:=ans+n;
for i:=2 to n do ans:=ans+n div i;
assign(f,'pair.out');
rewrite(f);
writeln(f,ans);

close(f);
  { TODO -oUser -cConsole Main : Insert code here }
end.