A spreadsheet is a rectangular array of cells.
All cells contain data or expressions that can be evaluated to obtain data.
You may assume that normal order of precedence operates. For an expression, if each cell referenced contains an integer, then the expression can be replaced by the integer to which the expression evaluates. You are to write a program which evaluates a series of simple spreadsheets. You may assume that there are no cases of self or cyclic cell references. The input consists of a sequence of simple spreadsheets.