mod=998244353

T=int(input())
for tests in range(T):
    N,X=map(int,input().split())

    if X%2==1:
        print(((N+1)//2)%mod)
    else:
        if N<X:
            print(((N+1)//2)%mod)
        elif N==X:
            print(((N+1)//2+1)%mod)
        else:
            ANS=(X+1)//2+1

            N-=X
            
            lo=N//(X+3)
            ANS+=lo*(X//2+2)

            rest=N-lo*(X+3)
            print((ANS+rest//2)%mod)