%{
#include <stdio.h>
 
int a_count = 0;
int b_count = 0;
%}
 
%%
a      { a_count++; }
b      { b_count++; }
\n     {
          if ((a_count % 2 == 0) && (b_count % 2 == 1)) {
              printf("ACCEPTED: Even a's and Odd b's\n");
          } else {
              printf("REJECTED: a_count = %d, b_count = %d\n", a_count, b_count);
          }
          // Reset for next input
          a_count = 0;
          b_count = 0;
      }
[^ab\n] { printf("Invalid character: %s\n", yytext); }
%%
 
int main() {
    printf("Enter strings (Ctrl+D or Ctrl+Z to end):\n");
    yylex();
    return 0;
}
 
int yywrap() {
    return 1;
}
 

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