Hieroglyphs

A team of researchers is studying the similarities between sequences of hieroglyphs. They represent each hieroglyph with a non-negative integer. To perform their study, they use the following concepts about sequences.

For a fixed sequence $A$, a sequence $S$ is called a subsequence of $A$ if and only if $S$ can be obtained by removing some elements (possibly none) from $A$.

The table below shows some examples of subsequences of a sequence $A = \[3, 2, 1, 2]$.

On the other hand, $\[3, 3]$ or $\[1, 3]$ are not subsequences of $A$.

Consider two sequences of hieroglyphs, $A$ and $B$. A sequence $S$ is called a common subsequence of $A$ and $B$ if and only if $S$ is a subsequence of both $A$ and $B$. Moreover, we say that a sequence $U$ is a universal common subsequence of $A$ and $B$ if and only if the following two conditions are met:

• $U$ is a common subsequence of $A$ and $B$.
• Every common subsequence of $A$ and $B$ is also a subsequence of $U$.

It can be shown that any two sequences $A$ and $B$ have at most one universal common subsequence.

The researchers have found two sequences of hieroglyphs $A$ and $B$. Sequence $A$ consists of $N$ hieroglyphs and sequence $B$ consists of $M$ hieroglyphs. Help the researchers compute a universal common subsequence of sequences $A$ and $B$, or determine that such a sequence does not exist.

• $1 ≤ N ≤ 100\\, 000$
• $1 ≤ M ≤ 100\\, 000$
• $0 ≤ A\[i] ≤ 200\\, 000$ for each $i$ such that $0 ≤ i < N$
• $0 ≤ B\[j] ≤ 200\\, 000$ for each $j$ such that $0 ≤ j < M$