import sys

def main():
    MOD = 998244353

    pref = [0, 1]

    ptr = [1 for _ in range(17)]
    b = [1 for _ in range(17)]
    md = [1 for _ in range(17)]
    ns = [1 for _ in range(17)]

    ln = 10 ** 6 + 10
    last = 1
    while (len(pref) <= ln):
        i = -1
        for j in range(2, 17):
            if (i == -1 or ns[j] < ns[i]):
                i = j
        mn = ns[i]
        if (mn > last):
            pref.append((pref[-1] + md[i] * ptr[i]) % MOD)
            last = mn
        ptr[i] += 1
        ns[i] += b[i]
        if (ptr[i] == i):
            ptr[i] = 1
            b[i] = b[i] * i + 1
            ns[i] = b[i]
            md[i] = (md[i] * i + 1) % MOD
            
    t = 10 ** 6
    rd = lambda: map(int, sys.stdin.readline().split())
    t, = rd()
    for _ in range(t):
        l = 1
        r = 10**6
        l, r = rd()
        ans = pref[r] - pref[l - 1]
        if (ans < 0):
            ans += MOD
        print(ans)

main()