#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  ll x;
  cin >> n >> x;
  x--;
  VL a(n);
  rep(i, n) cin >> a[i];
  constexpr int INF = 1001001001;
  segtree<int, [](int x, int y) { return min(x, y); }, []() { return INF; }> seg(VI(n + 1, 0));
  for (auto x : a) if (x <= n) seg.set(x, seg.get(x) + 1);
  for (int i = n; i < n + n + 1; i++) {
    int mex = seg.max_right(0, [](int x) { return x > 0; });
    a.emplace_back(mex);
    seg.set(mex, seg.get(mex) + 1);
    if (a[i-n] <= n) seg.set(a[i-n], seg.get(a[i-n]) - 1);
  }
  if (x <= n) {
    cout << a[x] << '\n';
  } else {
    x -= n;
    x %= n + 1;
    cout << a[n + x] << '\n';
  }
}