Choose the next instantaneous description for the PDA given the previous description, and

the following $$ function:

$(q_0,a,z)=\{(q_0,0z)\}$

$(q_0,a,0)=\{(q_0,00)\}$

$(q_0,b,0)=\{(q_1,)\}$

$(q_1,b,0)=\{(q_1,)\}$

$(q_1,b,z)=\{(q_1,z)\}$

$(q_1,,z)=\{(q_2,z)\}$

$(q_0,$aaab,$z)|--{?}^{**}(q_0,b,000z)|--?$

$(q_1,,00z)$

$(q_0,,00z)$

$(q_1,,000z)$

The string aaab is not accepted by the PDA.