Line-Calculator

Your task is to implement class Line Calculator. All methods in class should be support dot notation.
The priority of different operations should be kept in mind. It means, that 2 + 2 * 2 is 6, not 8.

Details:

• create class LineCalculator
• init class default value (number)
• add methods:
  1. add(number)
  2. subtract(number)
  3. multiply(number)
  4. devide(number)
  5. pow(number)
• when we use Line Calculator with NSlog() method, method should be print current result
• use MRC

Example:
LineCalculator *calc = [LineCalculator defaultValue:@2];
calc.add(@2).multiply(@2);
NSLog(@"%@", calc); // should be print 6

Test Data:
LineCalculator *calc = [LineCalculator defaultValue:@10];
calc.add(83); -> 93

LineCalculator *calc = [LineCalculator defaultValue:@4];
calc.pow(1).pow(1).pow(1).multiply(2).add(80).subtract(11).multiply(1).subtract(41).subtract(65); -> -29

LineCalculator *calc = [LineCalculator defaultValue:@6];
calc.add(14).subtract(16).add(36).multiply(1).subtract(46).add(57).pow(1); -> 51

LineCalculator *calc = [LineCalculator defaultValue:@10];
calc.pow(1).pow(1); -> 10

LineCalculator *calc = [LineCalculator defaultValue:@7];
calc.subtract(94).subtract(97).multiply(1).pow(1).multiply(1).pow(1).subtract(65).pow(1); -> -249

LineCalculator *calc = [LineCalculator defaultValue:@7];
calc.subtract(43).subtract(43).multiply(1).subtract(60).add(8).subtract(28); -> -159