#include <bits/stdc++.h>
using namespace std;
#define int long long
using i64 = long long;
int mod = 998244353;
i64 qp(int a, int b)
{
    int res = 1;
    a %= mod;
    while (b)
    {
        if (b & 1)
            res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
};

mt19937_64 rng((unsigned int)chrono::steady_clock::now().time_since_epoch().count());
#define all(x) x.begin(), x.end()
void solve()
{
    int n;
    cin >> n;
    vector<pair<int, int>> p(n);
    for (int i = 0; i < n; i++)
        cin >> p[i].first >> p[i].second, p[i].first--, p[i].second--;
    sort(all(p));

    vector<vector<int>> e(n + 1);
    vector<int> d(n + 1);
    for (int i = 0; i < n; i++)
    {
        int u = p[i].first;
        int v = p[i].second + 1;
        e[u].push_back(v);
        e[v].push_back(u);
    }
    int ans = 1;
    vector<int> dep(n + 1, -1);
    dep[0] = 0;
    function<void(int x, int fa)> dfs = [&](int x, int fa)
    {
        for (auto y : e[x])
        {
            if (y == fa)
                continue;
            if (dep[y] != -1)
                ans = 0;
            else
                dep[y] = dep[x] + 1, dfs(y, x);
        }
    };
    dfs(0, -1);
    cout << ans << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int T = 1;
    cin >> T;
    while (T--)
        solve();
}