#include <bits/stdc++.h>
using namespace std;

int main() {
    int t;
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    cin >> t;
    while (t--) {
        int n;
        cin >> n;
        int x, y;
        int l = 0, r = 0;
        for (int i = 0; i < n; i++) {
            cin >> x >> y;
            if (x == 1) {
                r = max(r, y);
            } else {
                l = max(l, y);
            }
        }
        
        if (n == 1) {
            if (l) cout << (l-1)+3 << endl;
            else cout << (r-1)+2 << endl;
            continue;
        }
        
        int res = 0;
        if (l >= r) {
            res = (l-1)+3;
        } else if (r-l == 1) {
            res = (l-1)+4;
        } else if (r-l >= 2) {
            res = (r-1)+2;
        }
        
        cout << res << endl;
    }
}