5 2
1 2 4 5 3

5

There are five possible sequences of operations, as follows: - Erase $1$ and add it to the beginning, which results in $(1,2,3,4,5)$. Then, erase $3$ and add it to the end, which results in $(1,2,4,5,3)$. - Erase $3$ and add it to the beginning, which results in $(3,1,2,4,5)$. Then, erase $3$ and add it to the end, which results in $(1,2,4,5,3)$. - Erase $3$ and add it to the end, which results in $(1,2,4,5,3)$. Then, erase $1$ and add it to the beginning, which results in $(1,2,4,5,3)$. - Erase $3$ and add it to the end, which results in $(1,2,4,5,3)$. Then, erase $3$ and add it to the end, which results in $(1,2,4,5,3)$. - Erase $5$ and add it to the end, which results in $(1,2,3,4,5)$. Then, erase $3$ and add it to the end, which results in $(1,2,4,5,3)$.

2 16
1 2

150994942

Two of the four kinds of operations have no effect on the sequence, and the other two swap the two elements. From this fact, we can show that there are $4^m/2 = 2^{31} = 2147483648$ sequences of operations - half of all possible sequences - that we want to count. Thus, the answer is $2147483648$ modulo $998244353$, that is, $150994942$.