Smallest Missing Multiple

You are given a set of integers $A$. Find the smallest positive integer that does not belong to the set $A$ and is divisible by a fixed number $k$.

Write a program that:

• reads the set $A$ and the number $k$ from standard input,
• computes the smallest positive integer that is not in $A$ and is divisible by $k$,
• prints the result to standard output.

The first line contains two integers $n$ and $k$ ($1 ≤ n ≤ 10^6$, $1 ≤ k ≤ 10^{12}$), separated by a single space. Here $n$ is the size (number of elements) of the set $A$. The second line contains $n$ integers $a_i$ ($1 ≤ a_i ≤ 10^{18}$), separated by single spaces, representing the elements of the set $A$. All $a_i$ are pairwise distinct.

Print, on the first and only line, the smallest positive integer that does not belong to the set $A$ and is divisible by $k$.