var f,g:text;
n,i,j:byte;
begin
assign(f,'tije.in');
reset(f);
readln(f,n);
close(f);
assign(g,'tije.out');
rewrite(g);
for i:=1 to n-1 do
for j:=n downto 1 do
writeln(g,j,' ',n+1);
for i:=n-1 downto 1 do
writeln(g,i,' ',n);
for i:=1 to n-1 do
for j:=n downto 1 do
writeln(g,n+1,' ',i);
if n=1 then begin
      writeln(g,'1',' ','2');
      writeln(g,'2',' ','1');
      end;
close(g);
end.