var v:array[1..1000001] of longint;
    n,s,i,j:longint;
begin
assign (input,'fractii.in');
reset (input);
readln (input,n);
s:=0;
close (input);
for i:=1 to n do
v[i]:=i-1;
for i:=1 to n do
begin
for j:=2*i to n+1 do
v[j]:=v[j]-v[i];
s:=s+v[i];
end;
assign (output,'fractii.out');
rewrite (output);
write(output,2*s+1);
close (output);
end.