type subd=1..1000000;
var i,j:subd;
    f,g:text;
    n,k:subd;
function cmmdc(i,j:subd):subd;
var r:word;
begin
r:=i;
while j<>0 do begin
      r:=i mod j;
      i:=j;
      j:=r; end;
cmmdc:=i;
end;
function nr(n,k:subd):subd;
begin
for i:=2 to n-1 do
    for j:=i+1 to n do
        if cmmdc(i,j)<>1 then k:=k-2;
nr:=k;
end;
begin
assign(f,'fractii.in');
assign(g,'fractii.out');
reset(f);
rewrite(g);
read(f,n);
k:=sqr(n)-n+1;
write(g,nr(n,k));
close(f);
close(g);
end.