#include <iostream>
#include <cstring>
#include <utility>
#include <vector>
#include <cstdio>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <complex>
#include <array>
#include <ctime>
#include <cassert>
#include <set>
#include <iomanip>
#include <random>
#include <cstdlib>
#include <chrono>
#include <bitset>

using namespace std;



int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        int c1 = 0, c2 = 0;
        for (int i = 0; i < n; i++) {
            int x, y; cin >> x >> y;
            if (x == 1) {
                c1 = max(c1, y);
            } else {
                c2 = max(c2, y);
            }
        }
        if (c2 >= c1) {
            cout << c2 + 2 << "\n";
        } else {
            if (c2 == 0 || c2 < c1 - 1) {
                cout << c1 + 1 << "\n";
            } else {
                cout << c1 + 2 << "\n";
            }
        }

    }

}