###############
# lexer stuff #
###############

tokens = ('NUM', 'LPAREN', 'RPAREN', 'PLUS', 'STAR')

def t_NUM(t):
    r'\d+'
    t.value = int(t.value)
    return t

t_LPAREN = r'\('
t_RPAREN = r'\)'
t_PLUS   = r'\+'
t_STAR   = r'\*'

t_ignore = ' '

def t_error(t):
    pass

import ply.lex as lex
lexer = lex.lex()

################
# parser stuff #
################

def p_exp(p):
    '''exp : plus_exp
           | term'''
    p[0] = p[1]

def p_plus_exp(p):
    '''plus_exp : exp PLUS term'''
    p[0] = p[1] + p[3]

def p_term(p):
    '''term : star_term
            | factor'''
    p[0] = p[1]

def p_star_term(p):
    '''star_term : term STAR factor'''
    p[0] = p[1] * p[3]

def p_factor(p):
    '''factor : paren_exp
              | NUM'''
    p[0] = p[1]

def p_paren_exp(p):
    '''paren_exp : LPAREN exp RPAREN'''
    p[0] = p[2]

def p_error(p):
	pass

import ply.yacc as yacc
parser = yacc.yacc()

########
# main #
########

import sys
print parser.parse(sys.argv[1])