var n,i,j,k,l,c:longint;

begin
assign(input,'tije.in');reset(input);
assign(output,'tije.out');rewrite(output);
readln(n);
//fac pentru fiecare coloana ordonarea dupa care trec la urmatoarea
for i:=1 to n-1 do
        begin
        c:=i+1;
        l:=1;
        for j:=n downto i+1 do
                begin
//fac interschimbarea intre v[j,i] si corespunzatoru'
                for k:=1 to l-1 do
                        writeln(c,' ',n+1);
                for k:=1 to j do
                        writeln(i,' ',n+1);
                writeln(c,' ',i);
//il mut pe ala interschimbat
                writeln(n+1,' ',c);
                for k:=1 to j-1 do
                        writeln(n+1,' ',i);
                for k:=1 to l-1 do
                        writeln(n+1,' ',c);
                inc(l);
                inc(c);
                end;
        end;
close(input);close(output);
end.