#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

int main() {
    int T;
    cin >> T;

    while (T--) {
        int N;
        ll X;
        cin >> N >> X;
        vector<int> C(N);
        for (int i = 0; i < N; i++) cin >> C[i];

        auto f = [&](ll x) {
            ll lo = x - 1, hi = INFL;
            while (hi - lo > 1) {
                ll mid = (hi + lo) / 2;

                int dif = -1;
                for (int i = 60; i >= 0; i--) {
                    if ((mid >> i & 1) != (x >> i & 1)) {
                        dif = i;
                        break;
                    }
                }

                vector<int> need;
                for (int i = 0; i < N; i++) {
                    if (!(x >> C[i] & 1)) {
                        need.push_back(C[i]);
                    }
                }

                if (!need.empty() && need.back() > dif) {
                    lo = mid;
                } else {
                    hi = mid;
                }
            }
            return hi;
        };

        ll ans = abs(f(X) - X) * 2;

        for (int i = 0; i < N; i++) {
            ll it = 1ll << C[i];
            if (it <= X) {
                it |= X & ((1ll << i) - 1);
                ll res = f(it);
                ans = min(ans, X - it * 2 + res);
            }
        }

        cout << ans << endl;
    }
}