#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
using mint=modint1000000007;
int main()
{
    int n;
    cin>>n;
    ll x;
    cin>>x;
    vector<int> a(3*n+1);
    for(int i=0;i<n;i++)cin>>a[i];
    vector<int> b=a;
    set<int> s;
    vector<int> cnt(n+2);
    for(int i=0;i<=n+1;i++)s.insert(i);
    for(int i=0;i<n;i++)if(a[i]>n+1)a[i]=n+1;
    for(int i=0;i<n;i++){
        cnt[a[i]]++;
        if(cnt[a[i]]==1)s.erase(a[i]);
    }
    for(int i=n;i<=3*n;i++){
        a[i]=(*s.begin());
        cnt[a[i-n]]--;
        if(cnt[a[i-n]]==0)s.insert(a[i-n]);
        cnt[a[i]]++;
        if(cnt[a[i]]==1)s.erase(a[i]);
    }
    //for(int i=0;i<=3*n;i++)cout<<a[i]<<(i+1==3*n?"\n":" ");
    x--;
    if(x<n)cout<<b[x]<<endl;
    else{
        x=(x-n)%(n+1);
        cout<<a[n+x]<<endl;
    }
    return 0;
}