%{
#include <stdio.h>
#include <stdlib.h>
void yyerror(const char *s);
int yylex(void);
%}
 
%token INTEGER
%left '+' '-'
%left '*' '/'
 
%%
S:
    E '\n'   { printf("Accepted\n"); exit(0); }
    ;
 
E:
    E '+' T  { /* do nothing */ }
  | E '-' T  { /* do nothing */ }
  | T
  ;
 
T:
    T '*' F  { /* do nothing */ }
  | T '/' F  { /* do nothing */ }
  | F
  ;
 
F:
    '(' E ')' 
  | INTEGER
  ;
%%
 
void yyerror(const char *s) {
    printf("%s - Invalid String\n", s);
    exit(1);
}
 
int main() {
    printf("Enter expression: ");
    yyparse();
    return 0;
}
 

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