type vector=array [0..1000000] of longint;
var f,g:text;i,l,n,j:longint;sum:qword;v:vector;
begin
assign(f,'fractii.in');
assign(g,'fractii.out');
reset(f);
rewrite(g);
read(f,n);
for i:=1 to n do v[i]:=n;
for i:=2 to n do begin
v[i]:=v[i]-(n div i);
l:=2;
repeat
j:=i*l;
v[j]:=v[j]-1;
inc(l);
until j>n;
end;
for i:=1 to n do
sum:=sum+v[i];
writeln(g,sum);
close(f);
close(g);
end.