// TLE: T(n+m)

#include <array>
#include <iostream>
#include <vector>

#include <atcoder/modint>

using mint = atcoder::modint998244353;

mint solve(uint32_t n, uint64_t m) {
    if (n > m) {
        uint64_t tmp = n;
        n = m, m = tmp;
    }
    std::vector<mint> f(n + m + 1);
    f[0] = 1;
    for (uint64_t i = 1; i <= n + m; ++i) {
        if (i <= n) {
            f[i] += f[i - 1] * 2 * i;
            if (i >= 2) f[i] += f[i - 2] * (i - 1);
        } else if (i <= m) {
            f[i] += f[i - 1] * (2 * n + 1);
            if (i >= 2) f[i] += f[i - 2] * n;
        } else {
            f[i] += f[i - 1] * 2 * (n + m + 1 - i);
            if (i >= 2) f[i] += f[i - 2] * (n + m + 1 - i);
        }
    }
    return f[n + m];
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    uint32_t t;
    std::cin >> t;
    for (uint32_t case_id = 0; case_id < t; ++case_id) {
        uint32_t n;
        uint64_t m;
        std::cin >> n >> m;

        std::cout << solve(n, m).val() << '\n';
    }
}