编写题解 3029: 逆波兰表达式

inver = input().split()
inver = inver[::-1]
def arithmetic(inver):
    if inver:
        alphabet = inver.pop()
        if alphabet == '+':
            return arithmetic(inver) + arithmetic(inver)
        elif alphabet == '-':
            return arithmetic(inver) - arithmetic(inver)
        elif alphabet == '*':
            return arithmetic(inver) * arithmetic(inver)
        elif alphabet == '/':
            return arithmetic(inver) / arithmetic(inver)
        return float(alphabet)
    else:
        pass
print('%.6f'%arithmetic(inver))