%{
	#include <stdio.h>
	int yylex()
	int yyerror(char *s)
	
%}
%token ALPHA DIGIT
%%
var:ALPHA
   |ALPHA
   |DIGIT
   ;
%%
int main()
{
	printf("enter the name of variables\n");
    yyparse();
    printf("valid variable");
	return 0;
}

int yyerror(char *s)
{
  printf("invalid variable")
  return 1;
}