mod = 998244353

t = int(input())
for i in range(t):
  n,x = map(int,input().split())
  if  x % 2 == 1:
    print(((n+1)//2) % mod)
  else:
    ans = x//2 + (n-x+1)//(x+3) * ((x+4)//2) + (n-x+1)%(x+3)//2 + 1
    ans %= mod
    print(ans)