def count_ways(L, W):
    # Initialize dp array
    dp = [[0] * (W + 1) for _ in range(L + 1)]
 
    # Base cases
    dp[0][0] = 1
 
    # Fill the dp array
    for i in range(L + 1):
        for j in range(W + 1):
            if i >= 1:
                dp[i][j] += dp[i - 1][j] * (j * 2 + (i == 1))
            if j >= 1:
                dp[i][j] += dp[i][j - 1] * (i * 2 + (j == 1))
            dp[i][j] %= 998244353
 
    return dp[L][W]
 
# Sample Testcase
L, W = map(int, input().split())
print(count_ways(L, W))
 

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