#include <iostream>
#include <cstdio>
using namespace std;

int main()
{
    int T, lmax = -10, rmax = -10, y, x, max = -10, n;
    cin >> T;
    for (int i = 0; i < T; i++)
    {
        cin >> n;
        for (int j = 0; j < n; j++)
        {
            cin >> x >> y;
            if (1 == x && rmax < y)
                rmax = y;
            if (2 == x && lmax < y)
                lmax = y;
            if (lmax == rmax - 1)
                max = lmax + 3;
            else
                max = lmax + 2 > rmax + 1 ? lmax + 2 : rmax + 1;
        }
        cout << max << endl;
        max = lmax = rmax = -10;
    }

    return 0;
}