#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

#include <atcoder/fenwicktree>
using namespace atcoder;

int main() {
    cin.tie(nullptr);
    
    ll N, X;
    cin >> N >> X;
    vector<int> A(N);
    rep(i, 0, N) cin >> A[i];
    
    --X;
    if (X < N) {
        cout << A[X] << '\n';
        return 0;
    }
    X -= N;
    
    vector<int> cnt(N + 10, 0);
    rep(i, 0, N) if (A[i] < N + 10) ++cnt[A[i]];
    fenwick_tree<int> BIT(N + 10);
    rep(i, 0, N + 10) if (cnt[i] > 0) BIT.add(i, 1);
    
    rep(i, 0, N + 1) {
        int ng = -1, ok = N + 5;
        while (ok - ng > 1) {
            int mid = (ok + ng) / 2;
            if (BIT.sum(0, mid + 1) == mid + 1) ng = mid;
            else ok = mid;
        }
        
        A.push_back(ok);
        
        if (ok < N + 10) {
            ++cnt[ok];
            if (cnt[ok] == 1) BIT.add(ok, 1);
        }
        
        if (A[i] < N + 10) {
            --cnt[A[i]];
            if (cnt[A[i]] == 0) BIT.add(A[i], -1);
        }
    }
    
    cout << A[X % (N + 1) + N] << '\n';
}