import sys
from itertools import permutations
import heapq
from collections import deque
import random

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

mod = 998244353

def mat_mul(X,Y):
    n,m = len(X),len(Y[0])
    res = [[0 for j in range(m)] for i in range(n)]
    for i in range(n):
        for j in range(m):
            for k in range(len(Y)):
                res[i][j] += X[i][k] * Y[k][j]
                res[i][j] %= mod
    return res

M = 10**7 + 100
F = [0] * M
F[0] = 1
F[1] = 2
for n in range(2,M):
    F[n] = F[n-1] * 2 * n  + F[n-2] * (n-1)
    F[n] %= mod



def mat_pow(A,K):
    E = [[1,0],[0,1]]
    while K:
        if K & 1:
            E = mat_mul(E,A)
        A = mat_mul(A,A)
        K >>= 1
    return E

def solve(n,m):
    if m <= n:
        n,m = m,n
    
    if n == 0:
        return 1
    
    res = [[F[n]],[F[n-1]]]
    X = mat_pow([[2*n+1,n],[1,0]],m-n)
    res = mat_mul(X,res)

    


    if m == n:
        return (res[0][0] * F[n] + res[1][0] * n * F[n-1])  % mod
    else:
        return (res[0][0] * F[n] + res[1][0] * n * F[n-1])  % mod

for _ in range(int(input())):
    n,m = mi()
    print(solve(n,m))