Gary's Calculator

Time Limit: 5000/1000 MS (Java/Others)

Memory Limit: 32768/32768 K (Java/Others)

Description

Gary has finally decided to find a calculator to avoid making simple calculational mistakes in his math exam. Unable to find a suitable calculator in the market with enough precision, Gary has designed a high-precision calculator himself. Can you help him to write the necessary program that will make his design possible?
For simplicity, you only need to consider two kinds of calculations in your program: addition and multiplication. It is guaranteed that all input numbers to the calculator are non-negative and without leading zeroes.

Input

There are multiple test cases in the input file. Each test case starts with one positive integer N (N < 20), followed by a line containing N strings, describing the expression which Gary's calculator should evaluate. Each of the N strings might be a string representing a non-negative integer, a "*", or a "+". No integer in the input will exceed 109.
Input ends with End-of-File.

Output

For each test case, please output one single integer (with no leading zeros), the answer to Gary's expression. If Gary's expression is invalid, output "Invalid Expression!" instead. Please use the format indicated in the sample output.

Sample Input

3 100 + 600 3 20 * 4 2 + 500 5 20 + 300 * 20

Sample Output

Case 1: 700 Case 2: 80 Case 3: Invalid Expression! Case 4: 6020

Hint

lcy

Source

2008 Asia Hangzhou Regional Contest Online

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