#pragma GCC optimize("Ofast", "unroll-loops")

#define FAST ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <bitset>
#include <sstream>
#include <deque>
#include <queue>
#include <random>
#include <cassert>
#include <stack>
#include <fstream>

using namespace std;

#define ll long long
#define ld long double
#define inf 1000000007
#define all(a) a.begin(), a.end()
#define files(in, out) freopen(in, "r", stdin); freopen(out, "w", stdout)

template<class T> inline void sort(T &a) { sort(all(a)); }
template<class T> inline T sorted(T a) { sort(a); return a; }
template<class T> inline istream& operator>>(istream& str, vector<T> &a) { for (auto &i : a) str >> i; return str; }

void solve() {
    int n, x;
    cin >> n >> x;
    vector<int> a;
    for (int k = 0; k < n; ++k) {
        int aa;
        cin >> aa;
        a.push_back(aa);
    }
    sort(all(a));
    int t = 0, tt = 0, xx = x;
    for (int i = 1; i <= n + xx; ++i) {
        for (int j = 0; j < n; ++j) {
            if (i != a[j] && j == n - 1) {
                //cout << "notfound " << i << ' ' << x << '\n';
                x--;
                a.push_back(i);
                tt++;
            }
            if (i == a[j]) {
                //cout << "found " << i << '\n';
                break;
            }
        }
        //cout << tt << '\n';
        if (x == 0) {
            break;
        }
    }
    sort(all(a));
    for (int l = 0; l < n+tt; ++l) {
        //cout << a[l] << ' ';
        if (a[l + 1] - a[l] > 1 || l == n+tt-1) {
            cout << a[l] << '\n';
            break;
        }
    }
}

signed main() {
    FAST;
    // files("goat4.in", "goat4.out");
    int f = 1;
    cin >> f;
    while (f--) {
        solve();
    }
    return 0;
}