/*
 * @Author: hesorchen
 * @Date: 2020-07-03 17:05:01
 * @LastEditTime: 2020-07-26 15:06:37
 * @Description: https://hesorchen.github.io/
 */
#include <map>
#include <set>
#include <list>
#include <queue>
#include <deque>
#include <cmath>
#include <stack>
#include <vector>
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
#define endl '\n'
#define PI acos(-1)
#define PB push_back
#define ll long long
#define INF 0x3f3f3f3f
#define mod 1000000007
#define pll pair<ll, ll>
#define lowbit(abcd) (abcd & (-abcd))
#define max(a, b) ((a > b) ? (a) : (b))
#define min(a, b) ((a < b) ? (a) : (b))

#define IOS                      \
    ios::sync_with_stdio(false); \
    cin.tie(0);                  \
    cout.tie(0);
#define FRE                              \
    {                                    \
        freopen("in.txt", "r", stdin);   \
        freopen("out.txt", "w", stdout); \
    }

inline ll read()
{
    ll x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = (x << 1) + (x << 3) + (ch ^ 48);
        ch = getchar();
    }
    return x * f;
}
//head==============================================================================

ll f(ll n)
{
    if (n == 1 || n == 0)
        return 0;
    return (n - 1) + (n - 2) + f(n - 2);
}

// int tong[2][100010];
map<ll, ll> mp1;
map<ll, ll> mp2;
int a1[100010];
int a2[100010];
int main()
{
    IOS;
    ll t;
    cin >> t;
    while (t--)
    {
        mp1.clear(), mp2.clear();
        fill(a1, a1 + 100010, 0);
        fill(a2, a2 + 100010, 0);
        ll n;
        cin >> n;

        ll ans = 0;

        for (int i = 1; i <= n; i++)
        {
            cin >> a1[i] >> a2[i];
            if (a1[i] == 1)
                mp1[a2[i]] = 1;
            else
                mp2[a2[i]] = 1;
        }
        for (int i = 1; i <= n; i++)
        {
            if (a1[i] == 1)
                ans = max(ans, a2[i] + 1);
            else
            {
                // cout << '\t' << a2[i] << endl;
                // cout << mp1[a2[i] + 1] << endl;
                if (mp1[a2[i] + 1])
                {
                    // cout << 22222 << endl;
                    ans = max(ans, a2[i] + 3);
                }
                else
                    ans = max(ans, a2[i] + 2);
            }
        }

        cout << ans << endl;
    }

    return 0;
}

/*
 
 */