#include <bits/stdc++.h>
#define rep(i, p, n) for (ll i = p; i < (ll)(n); i++)
#define rep2(i, p, n) for (ll i = p; i >= (ll)(n); i--)
using namespace std;
using ll = long long;
using ld = long double;
const double pi = 3.141592653589793;
const long long inf = 2 * 1e9;
const long long linf = 4 * 1e18;
const ll mod1 = 1000000007;
const ll mod2 = 998244353;
template <class T>
inline bool chmax(T &a, T b)
{
    if (a < b)
    {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return 1;
    }
    return 0;
}

// atcoder
#include <atcoder/all>
using namespace atcoder;
using mint1 = modint1000000007;
using mint2 = modint998244353;

vector<pair<ll, ll>> base = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

int main()
{

    //////////////////
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    //////////////////

    ll N, X;
    cin >> N >> X;
    vector<ll> A(N + 1), B(N + 1), C(N + 1);
    rep(i, 0, N)
    {
        cin >> A.at(i);
        if (A.at(i) <= N)
        {
            C.at(A.at(i))++;
        }
    }
    if (N >= X)
    {
        cout << A.at(X - 1);
        return 0;
    }
    priority_queue<ll, vector<ll>, greater<ll>> Q;
    rep(i, 0, N + 1)
    {
        if (C.at(i) == 0)
        {
            Q.push(i);
        }
    }
    rep(i, 0, N + 1)
    {
        B.at(i) = Q.top();
        C.at(Q.top())++;
        Q.pop();
        if (A.at(i) <= N)
        {
            C.at(A.at(i))--;
            if (C.at(A.at(i)) == 0)
            {
                Q.push(A.at(i));
            }
        }
        if (i == 0)
        {
            A.at(N) == B.at(0);
        }
    }
    cout << B.at(X % (N + 1));
}