mod=998244353

def solve():
  n,x=map(int,input().split())
  if x%2==1:
    lose=n//2
    print((n-lose)%mod)
    return
  lose=(n//(2*(x+1))*x)
  n%=(2*(x+1))
  lose+=min(x//2,n//2+1)
  n-=x+1
  lose+=max(0,min(x//2,n//2+1))
  ans=n+1-lose
  print(ans%mod)

for _ in range(int(input())):
  solve()