#include <bits/stdc++.h>
#define ls rt<<1
#define rs rt<<1|1
using namespace std;

typedef unsigned long long ll;
const ll inf = (1ll << 63);
const int maxn = 1000001;

int d[3][101000];
int main() {
    int t;
    scanf("%d", &t);
    while(t--) {
        int n;
        scanf("%d", &n);
        for(int i = 1; i <= 100000; i++) d[1][i] = d[2][i] = 0;
        for(int i = 1; i <= n; i++) {
            int x, y;
            scanf("%d%d", &x, &y);
            d[x][y] = 1;
        }
        int ans = 0;
        for(int i = 100000; i >= 1; i--) {
            if(d[1][i] || d[2][i]) {
                if(d[1][i] == 1) {
                    if(d[1][i - 1]) ans = i + 2;
                    else ans = i + 1;
                } else ans = i + 2;
                break;
            }
        }
        cout << ans << endl;
    }
    return 0;
}