digraph untitled
{
    charset = "UTF-8"; 
    
    start -> read0;
    read0 [label="read",shape="diamond"];
    
    read0 -> pop1 [label="a"];
    pop1 [label="pop", shape=diamond];
    
    pop1 -> read0 [label="b"];
    pop1 -> push0 [label="a"];
    
    push0 [label="push a",  shape=box];
    pop1 -> push1 [label="N"];
    push1 [label="push a",  shape=box];
    
    push0 -> push1;
    push1 -> read0;
    

    read0 -> pop3 [label="N"];
    pop3 [label="pop", shape=diamond];
    
    pop3 -> pop4 [label="a"];
    pop3 -> reject [label="b, N"];
    pop4 [label="pop", shape=diamond];
    pop4 -> reject [label="a, b"];
    pop4 -> accept [label="N"];
    
    
    read0 -> pop2 [label="b"];
    pop2 [label="pop", shape=diamond];
    
    pop2 -> push2 [label="b"];
    push2 [label="push b", shape=box];
    pop2 -> push3 [label="N"];
    push3 [label="push b", shape=box];
    push2 -> push3;
    
    pop2 -> pop5 [label="a"];
    pop5 [label="pop", shape=diamond];
    
    pop5 -> read0 [label="a"];
    pop5 -> push3 [label="b"];
    pop5 -> push4 [label="N"];
    
    push3 -> push4;
    push4 [label="push b", shape=box];
    push4 -> read0;

}