#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;

// 快速幂计算
int quick_pow(int base, int exp) {
    int result = 1;
    while (exp) {
        if (exp & 1) result = 1LL * result * base % MOD;
        base = 1LL * base * base % MOD;
        exp >>= 1;
    }
    return result;
}

// 预处理组合数
const int MAXN = 500000; // 最大回合数
int fact[MAXN + 1], invFact[MAXN + 1];

void precompute() {
    fact[0] = 1;
    for (int i = 1; i <= MAXN; i++) {
        fact[i] = 1LL * fact[i - 1] * i % MOD;
    }
    invFact[MAXN] = quick_pow(fact[MAXN], MOD - 2);
    for (int i = MAXN - 1; i >= 0; i--) {
        invFact[i] = 1LL * invFact[i + 1] * (i + 1) % MOD;
    }
}

int combination(int n, int k) {
    if (k < 0 || k > n) return 0;
    return 1LL * fact[n] * invFact[k] % MOD * invFact[n - k] % MOD;
}

// 检查是否满足比分要求
bool isValidScore(int sa, int sb) {
    return (max(sa, sb) >= 11 && abs(sa - sb) >= 2);
}

// 计算合法的获胜序列数量
int solve(int n, vector<pair<int, int>>& scores) {
    vector<vector<int>> dp(n + 1, vector<int>(n + 1, 0));
    dp[0][0] = 1;

    for (int i = 1; i <= n; i++) {
        int a = scores[i - 1].first, b = scores[i - 1].second;
        for (int sa = 0; sa <= n; sa++) {
            for (int sb = 0; sb <= n; sb++) {
                if (dp[sa][sb] == 0) continue;

                if (a == -1 && b == -1) { // 当前回合未知
                    dp[sa + 1][sb] = (dp[sa + 1][sb] + dp[sa][sb]) % MOD;
                    dp[sa][sb + 1] = (dp[sa][sb + 1] + dp[sa][sb]) % MOD;
                } else if (a == sa + 1 && b == sb) { // 当前回合A得分
                    dp[sa + 1][sb] = (dp[sa + 1][sb] + dp[sa][sb]) % MOD;
                } else if (a == sa && b == sb + 1) { // 当前回合B得分
                    dp[sa][sb + 1] = (dp[sa][sb + 1] + dp[sa][sb]) % MOD;
                }
            }
        }
    }

    int total = 0;
    for (int sa = 0; sa <= n; sa++) {
        for (int sb = 0; sb <= n; sb++) {
            if (isValidScore(sa, sb) && sa + sb == n) {
                total = (total + dp[sa][sb]) % MOD;
            }
        }
    }
    return total;
}

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

    precompute();

    int T;
    cin >> T;
    while (T--) {
        int n;
        cin >> n;
        vector<pair<int, int>> scores(n);
        for (int i = 0; i < n; i++) {
            cin >> scores[i].first >> scores[i].second;
        }
        cout << solve(n, scores) << '\n';
    }

    return 0;
}