Need to develop a simple batch spreadsheet processor. It must be able to process cells just like in a ordinary spreadsheet, but will use simplified expressions. Each cell may contain:

- Nothing
- Non-negative integer number.
- Text labels, which is started with ' symbol.
- expression, which is started with '=' symbol and may contain non-negative integers, cell references, and simple arithmetic operations. There are no parenthesis allowed, and all operations have equal priority. References consist of single letter followed by single digit.

These restrictions have been made in order to simplify parsing, because parsing implementation is not important part of this problem. You should safely rely on these restrictions. Here is the grammar for cells content:

<expression> = '=' <term> { <operation> <term> }
<term> = <cell reference> | <non-negative number>
<cell reference > = <letter> <digit>
<operation> = '+' | '-' | '*' | '/'
<text> = '''{<printable character>}

Sheet processing rules are:

- all expressions should be substituted with calculated results.
- all calculations should be taken with signed integer arithmetic.
- text cells should be evaluated to corresponding text without ' prefix.
- There are no operations on text labels allowed.
- in case of any error in cell evaluation resulting cell must contain word with error description started with '#' symbol. Use short, descriptive messages. Do not provide a legend of the error messages in the output.

The program should only use the standard library function/classes and never communicate with other programs, libraries or system components.

Input and Output

Program should take sheet description with formulas from the standard input, evaluate it, and print resulting table to the standard output. No other file should be read from or written to, including the standard error. Input data represented as tabulation-separated table. First line contains pair of integers separated with tabulation and designating the table's height and width, respectively. Then, from the next line the cells themselves come, each in the grammar described above.

The output must contain only the expected data (including error messages) and no extra information should be printed (including custom welcome text). The output must be formatted similar to the sample provided below.

Sample Input

3 4
12 =C2 3 'Sample
=A1+B1*C1/5 =A2*B1 =B3-C3 'Spread
'Test =4-3 5 'Sheet

Sample Output

12    -4  3 Sample
4    -16 -4 Spread
Test   1  5 Sheet

Solution Guidelines

Production code quality is a must. The shorter and easy to read solution is absolutely preferable. The solution must contain test cases and code used during the development of the solution. Don't forget to comment on the code where appropriate. The code must be robust against errors.

Suppose that this problem description define phase #1 of the project. You must implement nothing else than required for it. However, it's known that there is phase #2 planned, and requirements will be:

- extend formula language to handle text fields.
- optimize for performance on huge tables.

You will be asked to describe changes you would made to your solution during the phase #2 during the interview.