Merge pull request #1 from Valetudox/leap_year

Leap year
Merge pull request #2 from Valetudox/fizz_buzz

Fizz buzz
Merge pull request #3 from Valetudox/string_calculator

String calculator
calculator stat
Merge pull request #4 from Valetudox/calculator_stat

Calculator stat
Merge pull request #5 from Valetudox/calc_stat

Calculator stat