import sys
from collections import deque, Counter
sys.setrecursionlimit(5 * 10 ** 5)
from pypyjit import set_param
set_param('max_unroll_recursion=-1')
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

for _ in range(ii()):
    n, x = mi()
    k = n // x
    ans = 0
    ans += (k + 1) // 2
    n -= n // x
    ans += n // 2
    ans %= mod
    print(ans)