#include<bits/stdc++.h>
using namespace std;
using ll=long long;
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

void Solve(){
    int N;
    ll X;
    cin>>N>>X;
    vector<ll>A(N);
    for(int i=0;i<N;i++)cin>>A[i];
    X--;
    if(X<N){
        cout<<A[X]<<"\n";
        return;
    }
    X-=N-1;
    map<ll,int>mp;
    for(int i=0;i<N;i++){
        mp[A[i]]++;
    }
    int now=0;
    ll mex=0;
    while(mp.count(mex))mex++;
    ll val=-1;
    for(int t=0;t<4*N;t++){
        ll a=A[now];
        if(val==-1||mex<val){
            A.push_back(mex);
            mp[mex]++;
        }else{
            A.push_back(val);
            mp[val]++;
        }
        if(mp[a]==1){
            mp.erase(a);
            val=a;
        }else{
            mp[a]--;
            val=-1;
        }
        while(mp.count(mex))mex++;
        now++;
        X--;
        if(X==0){
            cout<<A.back()<<"\n";
            return;
        }
    }
    vector<ll>B;
    for(int i=0;i<=N;i++)B.push_back(A[(int)A.size()-1-i]);
    reverse(all(B));
    X--;
    cout<<B[X%(N+1)]<<"\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    Solve();
}