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

#define pb push_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
const int maxn = 2e3 + 70;
const int INF = 0x3f3f3f3f;
const ll inf = 0x3f3f3f3f3f3f3f3f;
const int MOD = 1e9 + 7;
const double eps = 1e-7;
const double PI = acos(-1.0);

int n, m;

int main(){
    //freopen("in.txt", "r", stdin);
    int T; cin>>T;
    while(T--){
        cin>>n;
        int y[2]={0,0};
        for(int i=0;i<n;i++){
            int x, t; scanf("%d %d",&x,&t); --x;
            y[x] = max(y[x], t);
        }
        printf("%d\n",max(y[0]+1,y[1]+2)+(y[1] && y[0]==y[1]+1));
    }
    return 0;
}