%{

#define YYDEBUG 1
#include <stdio.h>
#include <math.h>

 %}
      
 /* YACC Declarations */
 %token NUM
 %left '-' '+'
 %left '*' '/'
 %left NEG     /* negation--unary minus */
 %right '^'    /* exponentiation        */
      
 /* Grammar follows */
 %%
 input:    /* empty string */
              | input line
      ;
      
 line:     '\n'
           | exp '\n'  { printf("%d\n", $1); }
      ;
      
 exp:      NUM                     { $$ = $1;        }
              | exp '+' exp        { $$ = $1 + $3;   }
              | exp '-' exp        { $$ = $1 - $3;   }
              | exp '*' exp        { $$ = $1 * $3;   }
              | exp '/' exp        { $$ = $1 / $3;   }
              | '-' exp  %prec NEG { $$ = -$2;       }
              | exp '^' exp        { $$ = pow($1, $3);}
              | '(' exp ')'        { $$ = $2;        }
      ;
 %%
static char line[1024];

int advance(int n)
{
   int i;
   for (i=n; line[i]; i++) line[i-n] = line[i];
   line[i-n] = line[i];
}

int yylex()
{
   int tok;
   static int token_char;

   if (!strcmp(line, "")) {
      if (fgets(line, 1024, stdin) == NULL) { return -1; }
      }

   switch (line[0]) {
      case '\n': { advance(1); return '\n'; }
      case ' ': case '\t': { advance(1); return yylex(); }
      case '+': case '-': case '*': case '/': case '^': case '(': case ')':
	{
	int rv = line[0]; advance(1);
	return rv;
	}
      case '0': case '1':      case '2': case '3':      case '4': case '5':
      case '6': case '7':      case '8': case '9':      case '.': {
	yylval = atoi(line);
	while (isdigit(line[0]) || (line[0]=='.')) advance(1);
	return NUM;
	}
      }
}

int yyerror(char *s)
{
   fprintf(stderr, "%s\n", s); fflush(stderr);
}

int main()
{
//     yydebug = 1;
     yyparse();
}