15. 6.
3. 6.
4. 5.
https://drive.google.com/open?id=1CRlvmIBymW4CkBrpnBt39w1QUVuRIcaC
https://drive.google.com/open?id=1Sb-c7aQ6Xe6A-d-8KlNcdQO_-WDiRBdd
23. 3.