program C;
var
        f:text;
        i,n,kil,ii:int64;
begin
        assign(f,'pair.in');
        reset(f);
        read(f,n);
        close(f);
        assign(f,'pair.out');
        i:=n;
        while i>0 do begin
                ii:=i div 2;
                while ii>0 do begin
                        if (i mod ii=0) then begin
                                kil:=kil+1;
                                writeln(i,'-',ii);
                        end;
                        ii:=ii-1;
                end;
                i:=i-1;
        end;
        rewrite(f);
        write(f,kil);
        close(f);
end.