var fi, fo : text;
i,n,q:longint;
k:qword;
v:array[0..1000000] of longint;
begin
assign(input,'fractii.in'); reset(input); 
assign(output,'fractii.out'); rewrite(output);
read(n);
for i:=0 to n-1 do v[i+1]:=i;
k:=0;
for i:=2 to (n div 2)+1 do  begin
q:=2*i; while q<=n do begin
v[q]:=v[q]-v[i];
q:=q+i;
end;
end;
for i:=1 to n do k:=k+v[i];  k:=k*2+1;
write(fo,k); close(fo);
end.