T = int(input())

MOD = 998244353
for _ in range(T):
    W, H = map(int, input().split())
    dp = [[0]*3 for _ in range(H)]
    dp[0][0] = 1
    dp[0][1] = W
    if 4 <= W:
        dp[0][2] = W*(W-3)//2
    for i in range(H-1):
        dp[i+1][0] = sum(dp[i])%MOD
        dp[i+1][1] += dp[i][0]*W%MOD
        dp[i+1][1] %= MOD
        dp[i+1][1] += dp[i][1]*(W-1)%MOD
        dp[i+1][1] %= MOD
        dp[i+1][1] += dp[i][2]*(W-2)%MOD
        dp[i+1][1] %= MOD
        if 4 <= W:
            dp[i+1][2] += dp[i][0]*dp[0][2]%MOD
            dp[i+1][2] %= MOD
            if 4 < W:
                dp[i+1][2] += dp[i][1]*(dp[0][2]-(W-3))%MOD
                dp[i+1][2] %= MOD
                dp[i+1][2] += dp[i][2]*(dp[0][2]-((W-3)*2-1))%MOD
                dp[i+1][2] %= MOD
            else:
                dp[i+1][2] += dp[i][1]+dp[i][2]
                dp[i+1][2] %= MOD
    print(sum(dp[-1])%MOD)