繁星淼淼
Well, I only did the plus and minus operation, if considering paranthese, it'll take too long (I'm working ..... ;) )expr = raw_input()nums = []ops = []val = ''for i in expr:if i.isdigit():val += ielse:nums.append(int(val))ops.append(i)val = ''if len(val)>0:nums.append(int(val))nums.reverse()res = nums.pop()for i in ops:if i == '+':res += nums.pop()elif i == '-':res -= nums.pop()print res