Problem B
Booking a Room
In this problem, you should write a program to search for available rooms in a given hotel. The hotel has $r$ rooms, numbered from $1$ to $r$, and you will be given a list describing which of these rooms are already booked.
Input
The input consists of:

one line with two integers $r$ and $n$ ($1\leq r \leq 100$, $0 \leq n \le r$), the number of rooms in the hotel and the number of rooms that are already booked, respectively;

$n$ lines, each with an integer between $1$ and $r$ (inclusive), a room number that is already booked;
All $n$ room numbers of the already booked rooms are distinct.
Output
If there are available rooms, output the room number of any such room. Otherwise, output “too late”.
Sample Input 1  Sample Output 1 

100 5 42 3 2 99 1 
23 
Sample Input 2  Sample Output 2 

3 3 2 3 1 
too late 