#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5 + 5;
int T, n, p[MAXN], e[MAXN], cnt = 0;

bool f[MAXN];

int main () {
    freopen ("and_sorting.in", "r", stdin) ;
    freopen ("and_sorting.out", "w", stdout);
    scanf ("%d", &T);
    int k = -1;
    while (T --) {
        cnt = 0;
        scanf ("%d", &n);
        long long s = (1 << 21) - 1;
        for (int q = 0; q < n; ++q) {
            scanf ("%d", &p[q]);
            if (p[q] != q)  {
                s &= p[q];
                f[q] = false;
            }
            else f[q] = true;
        }
        printf ("%lld\n", s);
    }
    return 0;
}