e-olymp
Competitions

Programming Principles 1. Week 2. September 9 - 15. PART 2

Two-digit number

Integer n is given. Print Ok, if n is two-digit number and No otherwise.

Input

One integer n.

Output

Print Ok, if n is two-digit number and No otherwise.

Time limit 1 second
Memory limit 128 MiB
Input example #1
17
Output example #1
Ok
Input example #2
-123
Output example #2
No
Author Matviychuk Sergiy Volodymyrovych
Source "ABC programming"