First lab

Signed-off-by: MishkaRogachev <mishkarogachev@gmail.com>
Fixes and exeptions handling

Signed-off-by: MishkaRogachev <mishkarogachev@gmail.com>
Added some comments

Signed-off-by: MishkaRogachev <mishkarogachev@gmail.com>
Ln function realisation added

Signed-off-by: MishkaRogachev <mishkarogachev@gmail.com>