from functools import cmp_to_key
from sys import stdin
input = stdin.readline

mod = 998244353
fact = [1]
mx = 4 *10** 5 + 1
fact    =[-1] * (mx+1) #MOD下での階乗
inv     =[-1] * (mx+1) #MOD下での逆元
facti=[-1] * (mx+1) #MOD下での階乗の逆元
fact[0]=fact[1]=1
inv[1] = 1
facti[0]=facti[1] = 1
for i in range(2,mx+1):
    fact[i] = (fact[i-1]*i)%mod
    inv[i] = (-inv[mod%i]*(mod//i))%mod
    facti[i] = (facti[i-1]*inv[i])%mod

block = 900
t = int(input())
query = [[] for _ in range(2 * 10 ** 5 // block + 1)]
for i in range(t):
    n,m = map(int,input().split())
    query[n // block].append([m,n,i])
def c(n, r):
    if n < 0 or r < 0 or r > n:
        return 0
    return (fact[n] * facti[r] % mod) * facti[n-r] % mod
# query.sort(key=cmp_to_key(cmp))
answer = [0] * t
ans = 1
l = 1
r = 1
for i in range(len(query)):
    if not query[i]:
        continue
    query[i].sort(reverse=(i%2 == 1))
    for qi in query[i]:
        R, L, id = qi
        while l > L:
            l -= 1
            ans = (c(2*r, l+1) - 2*ans) % mod
        while l < L:
            ans = ((c(2*r, l+1) - ans) * facti[2]) % mod
            l += 1
        while r > R:
            ans = (ans - c(2*r-2, l-1)) % mod
            r -= 1
        while r < R:
            r += 1
            ans = (ans + c(2*r-2, l-1)) % mod
        answer[id] = str(ans)
print("\n".join(answer))