Question $1$

Write a function to check whether a user is valid user or not. If user is valid user then a welcome message should display with a token number. Token number will be generated based on first palindrome number of $N$ digits.

If the user is not valid user then the function should display "UserId or password is not valid, pls try again.".

All valid User$-$id and password should be stored in an array like below :$-$

$\backslash$table$[[$user$1,$pass$1],[$user$2,$pass$2],[$user$3,$pass$3],[$user$4,$pass$4]]$