{p_0} {p_1}
{p_2}
{p_3} {p_4} {p_5}
{p_6}
{p_7} {p_8} {p_9}
{p_10} {p_11} {p_12}
{p_13}
{p_14}
{p_15}
{p_16}
{p_17} {p_18} {p_19}
{p_20}