Problems
Two-digit number
Two-digit number
Integer $n$ is given. Print "\textbf{Ok}", if $n$ is two-digit number and "\textbf{No}" otherwise.
\InputFile
One integer $n$.
\OutputFile
Print "\textbf{Ok}", if $n$ is two-digit number and "\textbf{No}" otherwise.
Input example #1
17
Output example #1
Ok
Input example #2
-123
Output example #2
No