题解 | 丛林木马

import sys

# for line in sys.stdin:
    # a = line.split()
    # print(int(a[0]) + int(a[1]))
def solve():
    input = sys.stdin.readline
    a, b = list(input().split())
    mod = 998244353

    n, m = len(a), len(b)
    sm1 = sm2 = 0
    for x in a:
        sm1 = (sm1 * 10 + int(x)) % mod

    t = 1
    for x in b:
        sm2 = (sm2 * 10 + int(x)) % mod 
    
    res = len(a) * sm2 % mod + len(b) * sm1 % mod
    print(res % mod)


if __name__ == "__main__":
    t = int(input())
    for _ in range(t):
        solve()