var g,w,eg,cg:int64;
    i:longint;
begin
assign(input,'energii.in');reset(input);
assign(output,'energii.out');rewrite(output);
 readln(g,w);
  for i:=1 to g do begin
   read(eg,cg);writeln;
  end;
 write('-1');
close(input);close(output);
end.