#include <iostream>
#include <vector>
 
using namespace std;
 
int main()
{
    int t, n;
    long long temp;
    vector<long long> factors;
    cin >> t;
    while(t--) {
        cin >> n;
        while(n--) {
            cin >> temp; 
            factors.push_back(temp);
        }
        for(long long x = 0; x < 32769; x++) {
            long long sum = 0;
            long long copyX = 1;
            for(long long factor : factors) {
                sum += copyX*factor % 32768;
                copyX = copyX * x % 32768;
            }
            if (sum == 0) {
                cout << x << endl;
                break;
            }
        }
    }
    return 0;
}
 

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2
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