%start G

%%

G   : A12345678 B12345678 C12345678 B12345678 B123456780123456789 A123456780123456789
      B123456780123456789 B12345678;

A12345678
    : "a";

B12345678
    : "b";

C12345678
    : "c";

A123456780123456789
    : "ax";

B123456780123456789
    : "bx";