MOD = 998244353


def solve(N, X):
    res = N//(2*X)*X
    N %= 2*X
    res += min(N, X)//2
    if N >= X:
        N -= X
        res += N//2+1
    return res % MOD


def main():
    t = int(input())
    ans = []
    for _ in range(t):
        N, X = map(int, input().split())
        ans.append(solve(N, X))
    print(*ans, sep='\n')


main()