var i,s,n:integer;   f,g:text;

function cmmdc(p,q:integer):integer;
var r:integer;
begin
while(p>0)do
begin
r:=q mod p;
q:=p;
p:=r;
end;
cmmdc:=q;
end;

function ff(n:integer):integer;
var k,j:integer;
begin
k:=0;

if (n=3)or(n=2) then k:=0
                else for j:=2 to n-1 do
                if cmmdc(j,n)>1 then k:=k+1;
                ff:=k;

end;

begin
assign(f,'fractii.in');reset(f);
assign(g,'fractii.out');rewrite(g);
readln(f,n);
s:=2*n-1;
for i:=n downto 2 do
s:=s+2*(i-2-ff(i));
write(g,s);
close(f);
close(g);
end.