#include <bits/stdc++.h>
using namespace std;
#define int long long
#define si signed
#define sc(x) scanf("%lld",&(x));
#define fi first
#define se second
#define pb push_back
#define P pair<int,int>
#define endl '\n'
#define eps 1e-8
si main()
{
    int t;
    sc(t)
    int n,m;
    double b;
    int x,y;
     int v[3];
    while(t--){
        sc(n)
        v[1]=v[2] = 0;
        for(int i=0;i< n;i++){
            sc(x)sc(y)
            v[x] = max(v[x],y);
        }
        int ans = 0;
        if(v[1]==v[2]&&v[1] == 0){
            ans = 0;
        }
        else
        if(v[2] == 0){
            ans = v[1]+1;
        }else
        if(v[2]>=v[1]){
            ans = v[2]+2;
        }else if(v[1] == v[2]+1){
            ans = v[1]+2;
        } else {
            ans = v[1]+1;
        }
        cout<<ans<<'\n';
    }
}