#include <bits/stdc++.h>
#include <iostream>
#include <cstdio>
#define LL long long
#define inf 0x3f
const int mod = 1e9+7;
using namespace std;

//struct S{
//    int x,y;
//}s1[100005],s2[100005];
//
//bool cmp(S a,S b)
//{
//    return a.y < b.y;
//}

int main()
{
    int t,n;
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        int t1,t2;
        t1 = t2 = 0;
        for(int i = 1; i <= n; i++){
           int x,y;
           scanf("%d%d",&x,&y);
           if(x == 1){
            t1 = max(y,t1);
//           s1[t1].x = x;
//           s1[t1++].y = y;
           }
           else{
            t2 = max(y,t2);
//            s2[t2].x = x;
//            s2[t2++].y = y;
           }
        }
        int ans;
        if(t1 <= t2) ans = 2 + t2;
        else if(t1 == t2 + 1 && t2 != 0) ans = 2 + t2 + 1;
        else ans = max(t2 + 2,t1 + 1);
        printf("%d\n",ans);
//        sort(s1,s1+n,cmp);
//        sort(s2,s2+n,cmp);
    }
    return 0;
}