#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
    int T, n;
    scanf("%d", &T);
    while(T--) {
        scanf("%d", &n);
        vector<int> v;
        int mx = 0, my = 0;
        for(int i = 0, x, y; i < n; i++) {
            scanf("%d%d", &x, &y);
            if(x == 1) mx = max(mx, y);
            else my = max(my, y);
        }
        if(mx == 0) printf("%d\n", my + 2);
        else if(my == 0) printf("%d\n", mx + 1);
        else printf("%d\n", min(max(my + 4, mx + 2), max(my + 3, mx + 2 + (my < mx ? 1 : 0))) - 1);
    }
    return 0;
}