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

typedef long long ll;
typedef pair<ll,ll> ii;

const int kn = 5e4 + 5, sqr = 223;

#define ff(i,n) for(int i = 1; i<=n;i++)
#define _ff(i,n) for(int i = n; i>=1; i--)

struct Query
{
	int l, r, id;
}qr[5001];

bool optionqr(Query a, Query b)
{
	if(int(a.r/sqr) != int(b.r/sqr)) return int(a.r/sqr) < int(b.r/sqr);
	return a.l < b.l;
}

struct Trie
{
	multiset<int> val;
	int c[2];
	Trie()
	{
		c[0] = c[1] = -1;
	}
}trie[2][kn];

int n, q;
int a[kn], top = 0;

int F(int i)
{
	int tmp = i%4;
	if(tmp == 0) return i;
	if(tmp == 1) return 1;
	if(tmp == 2) return i+1;
	return 0;
}

void add(int num, int k)
{
	int p = 0;
	int X = (num == 1) ? F(k) : F(k-1);
	for(int i = 19; i>=0; i--)
	{
		trie[num][p].val.insert(k);
		int tmp = (X>>i)&1;
		if(trie[num][p].c[tmp] == -1) trie[num][p].c[tmp] = ++top;
		p = trie[num][p].c[tmp];
		if(i==0) trie[num][p].val.insert(k);
	}
}

void dele(int num, int k)
{
	int p = 0;
	int X = (num == 1) ? F(k) : F(k-1);
	for(int i = 19; i>=0; i--)
	{
		auto it = trie[num][p].val.find(k);
		trie[num][p].val.erase(k);
		int tmp = (X>>i)&1;
		p = trie[num][p].c[tmp];
		if(i==0)
		{
			it = trie[num][p].val.find(k);
			trie[num][p].val.erase(it);
		}
	}
}

int findtrie0(int k)
{
	int p = 0, X = F(k);
	//cout << X << endl;
	bool larger = false;
	for(int i = 19; i>=0; i--)
	{
		int tmp = (X>>i)&1;
		int cur = -1;
		if(not (trie[0][p].c[1-tmp] == -1 || not (trie[0][trie[0][p].c[1-tmp]].val).size() || *(trie[0][trie[0][p].c[1-tmp]].val).begin() > k) )
		{
			cur = 1-tmp;
			if(not larger) larger = true;
			//cout <<"ok "<<i << endl;
		}
		else
		{
			if(not larger && tmp == 1) return X;
			cur = tmp;
		}
		if(cur == -1) return 696969669;
		p = trie[0][p].c[cur];
		if(i==0) return (F(*trie[0][p].val.begin() -1)^X);
	}

}

int findtrie1(int X)
{

}

int main()
{
	add(0,21); add(0,5); dele(0,21);
	cout << findtrie0(104);
	scanf("%d %d", &n, &q);
	ff(i,n)
	{
		scanf("%d", &a[i]);
	}
	ff(i,q)
	{
		scanf("%d %d %d", &qr[i].l, &qr[i].r);
		qr[i].id = i;
	}
	sort(qr+1, qr+q+1, optionqr);

}