There is an n×mntimes mn×m chessboard, you need to cover it with 1×21times 21×2 dominos, each cell should be covered exactly once. Each possible position of a domino has been given an integer in [
There is an n×mntimes mn×m chessboard, you need to cover it with 1×21times 21×2 dominos, each cell should be covered exactly once. Each possible position of a domino has been given an integer in [1,998244352][1,998244352][1,998244352], the value of a covering pattern is the product of integers on the dominos' positions. Please calculate the sum of values of all covering patterns, modulo 998244353998244353998244353.
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