mod = 998244353
for _ in range(int(input())):
    n, x = map(int, input().split())
    n += 1
    if x % 2:
        print(n // 2 % mod)
    else:
        period = x + 3
        cnt = (period + 1) // 2
        ans = n // period * cnt
        n %= period
        if n <= x:
            ans += n // 2
        else:
            ans += x // 2 + 1
        print(ans % mod)