#include<bits/stdc++.h>
using namespace std;

int main(){
	int n;
	cin >> n;
	long long x;
	cin >> x;
	vector<int> a(n);
	for(int i = 0; i < n; i++) cin >> a[i];
	if(x <= n){
		cout << a[x - 1] << "\n";
		return 0;
	}
	
	vector<int> idx(n + 1, -1);
	for(int i = 0; i < n; i++){
		if(a[i] <= n) idx[a[i]] = i;
	}
	
	vector<int> b(n + 1, -1);
	int nxt = 0;
	for(int i = 0; i <= n; i++){
		while(b[nxt] != -1) nxt++;
		b[max(nxt, idx[i] + 1)] = i;
	}
	cout << b[(x - n - 1) % (n + 1)] << "\n";
	return 0;
}