The purpose of this challenge is to use looping $($WHILE$)$ and conditional constructs $($IF$-$ELSE, IF$-$ELSE$-$IF$,$ nested IF statements$).$ This challenge simulates a hotel reservation system.

Requirements

Ask the user to enter their first name. Don't forget to first declare a variable for the first name.

Ask the user to enter their last name. Don't forget to first declare a variable for the last name.

Ask the user to enter their age. Don't forget to first declare a variable for the age.

If the user is younger than $21$ yrs old, display a message indicating that they cannot make a hotel reservation and ask the user again to enter a valid age. HINT: This is Input Validation that uses a WHILE loop. The program won't continue past this point if the user keeps entering an age younger than $21.$