Added solution of GCD and LCM (Part 1) and Count Letters in a word

[mauryahimanshu]

Description

Program Name - GCD and LCM (Part 1)
Program Name - Count Letters in a Word Search Issue No.- #181 Issue No.- #161

Checklist(self check)

• [ ] Yes, this task assigned to me.
• [x] My code follows the style guidelines(Clean Code) of this project
• [x] I have performed a self-review of my own code
• [x] My Filename is in camelCase format
• [x] I have added Problem statement, Problem link in file.

[aayushi-droid]

Only give solution which task assigned to you. delete Gcd file and commit again

thanks