Professor Octastichs has invented a new program- ming language, Smeech. An expression in Smeech may be a positive or negative integer, or may be of the form (p e1 e2) where p is a real number between 0 and 1 (inclusive) and e1 and e2 are Smeech expres- sions. The value represented by a Smeech expression is as follows: • An integer represents itself • With probability p, (p e1 e2) represents x + y where x is the value of e1 and y is the value of e2; otherwise it represents x − y. Given a Smeech expression, what is its expected value? Input Input consists of several Smeech expressions, one per line, followed by a line containing ‘()’. Output For each expression, output its expected value to two decimal places. Sample Input 7 (.5 3 9) () Sample Output 7.00 3.00