var f,g:text;
    p,i,j,n:longint;
    a:array[1..100000]of longint;

 begin
assign(f,'fractii.in');
assign(g,'fractii.out');
reset(f);
rewrite(g);
read(f,n);
 for i:=1 to n do
  a[i]:=i-1;
 p:=0;
  for i:=2 to n do
  begin
p:=p+a[i];
j:=i*2;
 while j<=n do
begin
 a[j]:=a[j]-a[i];
 j:=j+i;
end;
end;
 write(g,p*2+1);
close(f);
close(g);
end.