#include <fstream>
#include <algorithm>
#include <vector>
#define ifs ifstream
#define ofs ofstream
#define XProgram
using namespace std;
ifs fin("asm_game.in");
ofs fout("asm_game.out");
vector<int> c[500010];
int flag[500010];
int m,n,u,v,ans=0;
#ifdef XProgram
int load()
{
	fin>>m>>n;
	for(int i=1;i<=m;i++)
	{
		fin>>u>>v;
		c[u].push_back(u);
		flag[u]+=1;
		c[v].push_back(v);
		flag[v]+=1;
	}
	return 0;
}
int work(int x)
{
	for(int i=1;i<=c[x].size();i++)
	{
		flag[c[x][i]]--;
		if(flag[c[x][i]]<=3&&flag[c[x][i]]>=0)
			work(c[x][i]);
	}
	return 0;
}
int popo()
{
	for(int i=1;i<=n;i++)
	{
		if(flag[i]<3)
			work(i);
	}
	for(int i=1;i<=n;i++)
	{
		if(flag[i]>=3)
		{
			ans^=i;
		}
	}
	return 0;
}
int main()
{
	load();
	popo();
	fout<<ans<<endl;
	#endif
	return 0;
}