#include<iostream>
#include<vector>
#include<algorithm>
#include<iomanip>
#include<queue>
#include<map>
using namespace std;
#define OVERLOAD_REP(_1, _2, _3, name, ...) name
#define REP1(i, n) for (auto i = std::decay_t<decltype(n)>{}; (i) != (n); ++(i))
#define REP2(i, l, r) for (auto i = (l); (i) != (r); ++(i))
#define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
#define REP(i, l, r) rep(i, l, r+1)
#define all(x) (x).begin(),(x).end()
#define inf 1000000000
using ll = long long;
using P = pair<int,int>;
using Graph = vector<vector<int> >;

int main() {
    // 高速化
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    // 小数点の出力桁数を指定
    cout << fixed << setprecision(10);

    // メイン
    ll N, X;
    cin >> N >> X;
    vector<int> A(N);
    rep(i, 0, N) cin >> A[i];
    vector<int> B(A);
    sort(all(B));
    int cur = 0;
    priority_queue<int, vector<int>, greater<int> > que;
    rep(i, 0, N) {
        while(binary_search(all(B), cur)) {
            cur++;
        }
        que.push(cur);
        cur++;
    }

    map<int, int> m;
    rep(i, 0, N) m[A[i]]++;

    vector<int> shuki;
    rep(i, 0, N+1) {
        int a = que.top();
        que.pop();
        shuki.push_back(a);
        //cout << a << endl;
        m[a]++;
        m[A[i]]--;
        if(m[A[i]] == 0) que.push(A[i]);
    }

    if(X > N) cout << shuki[(X-N-1)%shuki.size()] << endl;
    else cout << A[X-1] << endl;

    return 0;
}