iiitv/ChefLib

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// ~~~~~~~© Aashutosh Rathi~~~~~~
// ~~~~~~~~aashutosh001~~~~~~~~~~
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <bits/stdc++.h>
#include <algorithm>
#include <stdio.h>
/*
    Aashutosh Rathi
    Code Chef March Long Problem 2
    Bear and Extra Number
*/
using namespace std;
typedef long int BIG;
typedef long long int PAPA;

int main()
{
    int t;
    scanf("%d",&t);
    while(t--){
        BIG n,i,c=0;
        scanf("%ld",&n);
        PAPA a[n];
        for(i=0;i<n;i++){
            scanf("%lld",&a[i]);
        }
        sort(a,a+n);
        for(i=0;i<n-1;i++){
            if(a[i+1] != (a[i]+1) && i<n-2){
                printf("%lld\n",a[i]);
                break;
            }
            else if(i>=n-2){
                printf("%lld\n",a[n-1]);
                break;
            }
        }

    }
    return 0;
}