var n,i,j,s:longint;f,g:text;
function func(a,b:longint):longint;
var r:longint;
begin
while r<>0 do begin
r:=a mod b;
a:=b;
b:=r;
end;
func:=a;
end;
begin
assign(f,'functii.in');reset(f);
assign(g,'functii.out');rewrite(g);
read(f,n);
for i:=2 to n do begin s:=s+i-1;
for j:=1 to i-1 do begin
write(i,j);
if func(i,j)<>1 then s:=s-1;end;
end;
s:=(s*2)+1;
writeln(g,s);
readln;
close(f);
close(g);
end.